RNAi Inhibition of Alpha-ENaC Expression

ABSTRACT

The invention relates to compositions and methods for modulating the expression of alpha-ENaC, and more particularly to the downregulation of alpha-ENaC expression by chemically modified oligonucleotides.

TECHNICAL FIELD

The invention relates to the field of ENaC-mediated airway ion transportand compositions and methods for modulating alpha-ENaC expression, andmore particularly to the down-regulation of alpha-ENaC byoligonucleotides via RNA interference which are administered locally tothe lungs and nasal passage via inhalation/intranasal administration, orare administered systemically, e.g. by via intravenous injection.

BACKGROUND

RNA interference or “RNAi” is a term initially coined by Fire andco-workers to describe the observation that double-stranded RNA (dsRNA)can block gene expression when it is introduced into worms (Fire et al.,Nature 391:806-811, 1998). Short dsRNA directs gene-specific,post-transcriptional silencing in many organisms, including vertebrates,and has provided a new tool for studying gene function. This technologyhas been reviewed numerous times recently, see, for example Novina, C.D., and Sharp, P., Nature 2004, 430:161, and Sandy, P., et al.,Biotechniques 2005, 39:215, hereby incorporated by reference.

The mucosal surfaces at the interface between the environment and thebody have evolved a number of protective mechanisms. A principal form ofsuch innate defense is to cleanse these surfaces with liquid. Typically,the quantity of the liquid layer on a mucosal surface reflects thebalance between epithelial liquid secretion, often reflecting anion (Cl⁻and or HCO₃ ⁻) secretion coupled with water (and a cation counter-ion),and epithelial liquid absorption, often reflecting Na⁺ absorption,coupled with water and counter anion (Cl⁻ and or HCO₃ ⁻). Many diseasesof mucosal surfaces are caused by too little protective liquid on thosemucosal surfaces created by an imbalance between secretion (too little)and absorption (relatively too much). The defective salt transportprocesses that characterize these mucosal dysfunctions reside in theepithelial layer of the mucosal surface. One approach to replenish theprotective liquid layer on mucosal surfaces is to “re-balance” thesystem by blocking Na⁺ channel mediated liquid absorption. Theepithelial protein that mediates the rate-limiting step of Na⁺ andliquid absorption is the epithelial Na⁺ channel (ENaC). Alpha-ENaC ispositioned on the apical surface of the epithelium, i.e. the mucosalsurface-environmental interface. Inhibition of alpha-ENaC mediated Na⁺mediated liquid absorption may achieve therapeutic utility. Therefore,there is a need for the development of effective therapies for thetreatment and prevention of diseases or disorders in which alpha-ENaC isimplicated, e.g. cystic fibrosis in humans and animals, and particularlyfor therapies with high efficiency. One prerequisite for high efficiencyis that the active ingredient is not degraded too quickly in aphysiological environment.

SUMMARY

The present invention provides specific compositions and methods thatare useful in reducing alpha-ENaC levels in a subject, e.g., a mammal,such as a human, e.g. by inhaled, intranasal or intratrachealadministration of such agents.

The present invention specifically provides iRNA agents consisting of,consisting essentially of or comprising at least 15 or more contiguousnucleotides for alpha-ENaC, and more particularly agents comprising 15or more contiguous nucleotides from one of the sequences provided inTables 1A-1D. The iRNA agent preferably comprises less than 30nucleotides per strand, e.g., 21-23 nucleotides, such as those providedin Tables 1A-1D. The double stranded iRNA agent can either have bluntends or more preferably have overhangs of 1-4 nucleotides from one orboth 3′ ends of the agent.

Further, the iRNA agent can either contain only naturally occurringribonucleotide subunits, or can be synthesized so as to contain one ormore modifications to the sugar, phosphate or base of one or more of theribonucleotide subunits that is included in the agent. The iRNA agentcan be further modified so as to be attached to a ligand that isselected to improve stability, distribution or cellular uptake of theagent, e.g. cholesterol. The iRNA agents can further be in isolated formor can be part of a pharmaceutical composition used for the methodsdescribed herein, particularly as a pharmaceutical compositionformulated for delivery to the lungs or nasal passage or formulated forparental administration. The pharmaceutical compositions can contain oneor more iRNA agents, and in some embodiments, will contain two or moreiRNA agents, each one directed to a different segment the alpha-ENaCgene.

One aspect of the present invention relates to a double-strandedoligonucleotide comprising at least one non-natural nucleobase. Incertain embodiments, the non-natural nucleobase is difluorotolyl,nitroindolyl, nitropyrrolyl, or nitroimidazolyl. In a preferredembodiment, the non-natural nucleobase is difluorotolyl. In certainembodiments, only one of the two oligonucleotide strands comprising thedouble-stranded oligonucleotide contains a non-natural nucleobase. Incertain embodiments, both of the oligonucleotide strands comprising thedouble-stranded oligonucleotide independently contain a non-naturalnucleobase.

The present invention further provides methods for reducing the level ofalpha-ENaC mRNA in a cell. Such methods comprise the step ofadministering one of the iRNA agents of the present invention to asubject as further described below. The present methods utilize thecellular mechanisms involved in RNA interference to selectively degradethe target RNA in a cell and are comprised of the step of contacting acell with one of the iRNA agents of the present invention. Such methodscan be performed directly on a cell or can be performed on a mammaliansubject by administering to a subject one of the iRNAagents/pharmaceutical compositions of the present invention. Reductionof target RNA in a cell results in a reduction in the amount of encodedprotein produced, and in an organism, results in reduction of epithelialpotential difference, decreased fluid absorption and increasedmucociliary clearance.

The methods and compositions of the invention, e.g., the methods andiRNA agent compositions can be used with any dosage and or formulationdescribed herein, as well as with any route of administration describedherein.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thisdescription, the drawings, and from the claims. This applicationincorporates all cited references, patents, and patent applications byreferences in their entirety for all purposes.

In the Figures:

FIG. 1: Restriction digest map of pXoon construct for cloned cynomolgousα-EnaC.

FIG. 2: Cloning of the predicted off-target and the on-targetrecognition sites into the AY535007 dual luciferase reporter construct.Fragments consist of 19 nt of the predicted target site and 10 nt offlanking sequence at both the 5′ and 3′ ends.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS OF THE INVENTION

For ease of exposition the term “nucleotide” or “ribonucleotide” issometimes used herein in reference to one or more monomeric subunits ofan RNA agent. It will be understood that the usage of the term“ribonucleotide” or “nucleotide” herein can, in the case of a modifiedRNA or nucleotide surrogate, also refer to a modified nucleotide, orsurrogate replacement moiety, as further described below, at one or morepositions.

An “RNA agent” as used herein, is an unmodified RNA, modified RNA, ornucleoside surrogate, each of which is described herein or is well knownin the RNA synthetic art. While numerous modified RNAs and nucleosidesurrogates are described, preferred examples include those which havegreater resistance to nuclease degradation than do unmodified RNAs.Preferred examples include those that have a 2′ sugar modification, amodification in a single strand overhang, preferably a 3′ single strandoverhang, or, particularly if single stranded, a 5′-modification whichincludes one or more phosphate groups or one or more analogs of aphosphate group.

An “iRNA agent” (abbreviation for “interfering RNA agent”) as usedherein, is an RNA agent, which can downregulate the expression of atarget gene, e.g. ENaC gene SCNN1A. While not wishing to be bound bytheory, an iRNA agent may act by one or more of a number of mechanisms,including post-transcriptional cleavage of a target mRNA sometimesreferred to in the art as RNAi, or pre-transcriptional orpre-translational mechanisms.

A “ds iRNA agent” (abbreviation for “double stranded iRNA agent”), asused herein, is an iRNA agent which includes more than one, andpreferably two, strands in which interstrand hybridization can form aregion of duplex structure. A “strand” herein refers to a contigououssequence of nucleotides (including non-naturally occurring or modifiednucleotides). The two or more strands may be, or each form a part of,separate molecules, or they may be covalently interconnected, e.g., by alinker, e.g., a polyethyleneglycol linker, to form one molecule. Atleast one strand can include a region which is sufficientlycomplementary to a target RNA. Such strand is termed the “antisensestrand.” A second strand of the dsRNA agent, which comprises a regioncomplementary to the antisense strand, is termed the “sense strand.”However, a ds iRNA agent can also be formed from a single RNA moleculewhich is at least partly self-complementary, forming, e.g., a hairpin orpanhandle structure, including a duplex region. The latter are hereinreferred to as short hairpin RNAs or shRNAs. In such case, the term“strand” refers to one of the regions of the RNA molecule that iscomplementary to another region of the same RNA molecule.

Although, in mammalian cells, long ds iRNA agents can induce theinterferon response which is frequently deleterious, short ds iRNAagents do not trigger the interferon response, at least not to an extentthat is deleterious to the cell and or host (Manche et al., Mol. Cell.Biol. 12:5238, 1992; Lee et al., Virology 199:491, 1994; Castelli etal., J. Exp. Med. 186:967, 1997; Zheng et al., RNA 10:1934, 2004; Heidelet al., Nature Biotechnol. 22 1579). The iRNA agents of the presentinvention include molecules which are sufficiently short that they donot trigger a deleterious non-specific interferon response in normalmammalian cells. Thus, the administration of a composition including aniRNA agent (e.g., formulated as described herein) to a subject can beused to decrease expression of alpha-ENaC in the subject, whilecircumventing an interferon response. Molecules that are short enoughthat they do not trigger a deleterious interferon response are termedsiRNA agents or siRNAs herein. “siRNA agent” or “siRNA” as used herein,refers to an iRNA agent, e.g., a ds iRNA agent, that is sufficientlyshort that it does not induce a deleterious interferon response in amammalian, and particularly a human, cell, e.g., it has a duplexedregion of less than 60 but preferably less than 50, 40, or 30 nucleotidepairs.

The isolated iRNA agents described herein, including ds iRNA agents andsiRNA agents, can mediate the decreased expression of alpha-ENaC, e.g.,by RNA degradation. For convenience, such RNA is also referred to hereinas the RNA to be silenced. Such a nucleic acid is also referred to as a“target RNA”, sometimes “target RNA molecule” or sometimes “targetgene”.

As used herein, the phrase “mediates RNAi” refers to the ability of anagent to silence, in a sequence-specific manner, a target gene.“Silencing a target gene” means the process whereby a cell containingand or expressing a certain product of the target gene when not incontact with the agent, will contain and or express at least 10%, 20%,30%, 40%, 50%, 60%, 70%, 80%, or 90% less of such gene product whencontacted with the agent, as compared to a similar cell which has notbeen contacted with the agent. Such product of the target gene can, forexample, be a messenger RNA (mRNA), a protein, or a regulatory element.

As used herein, the term “complementary” is used to indicate asufficient degree of complementarity such that stable and specificbinding occurs between a compound of the invention and a target RNAmolecule, e.g., alpha-ENaC mRNA. Specific binding requires a sufficientdegree of complementarity to avoid non-specific binding of theoligomeric compound to non-target sequences under conditions in whichspecific binding is desired, i.e., under physiological conditions in thecase of in vivo assays or therapeutic treatment, or in the case of invitro assays, under conditions in which the assays are performed. Thenon-target sequences typically differ from the target sequences by atleast 2, 3 or 4 nucleotides.

As used herein, an iRNA agent is “sufficiently complementary” to atarget RNA, e.g., a target mRNA (e.g., alpha-ENaC mRNA) if the iRNAagent reduces the production of a protein encoded by the target RNA in acell. The iRNA agent may also be “exactly complementary” to the targetRNA, e.g., the target RNA and the iRNA agent anneal, preferably to forma hybrid made exclusively of Watson-Crick basepairs in the region ofexact complementarity. A “sufficiently complementary” iRNA agent caninclude an internal region (e.g., of at least 10 nucleotides) that isexactly complementary to a target alpha-ENaC RNA. Moreover, in someembodiments, the iRNA agent specifically discriminates asingle-nucleotide difference. In this case, the iRNA agent only mediatesRNAi if exact complementarity is found in the region (e.g., within 7nucleotides of) the single-nucleotide difference. Preferred iRNA agentswill be based on or consist of or comprise the sense and antisensesequences provided in Tables 1A-1D.

As used herein, “essentially identical” when used referring to a firstnucleotide sequence in comparison to a second nucleotide sequence meansthat the first nucleotide sequence is identical to the second nucleotidesequence except for up to one, two or three nucleotide substitutions(e.g., adenosine replaced by uracil). “Essentially retaining the abilityto inhibit alpha-E-NaC expression in cultured human cells,” as usedherein referring to an iRNA agent not identical to but derived from oneof the iRNA agents of Tables 1A-1D by deletion, addition or substitutionof nucleotides, means that the derived iRNA agent possesses aninhibitory activity not less than 20% of the inhibitory activity of theiRNA agent of Tables 1A-1D from which it was derived. For example, aniRNA agent derived from an iRNA agent of Tables 1A-1D which lowers theamount of alpha-ENaC mRNA present in cultured human cells by 70% mayitself lower the amount of mRNA present in cultured human cells by atleast 50% in order to be considered as essentially retaining the abilityto inhibit alpha-ENaC replication in cultured human cells. Optionally,an iRNA agent of the invention may lower the amount of alpha-ENaC mRNApresent in cultured human cells by at least 50%.

As used herein, a “subject” refers to a mammalian organism undergoingtreatment for a disorder mediated by alpha-ENaC. The subject can be anymammal, such as a cow, horse, mouse, rat, dog, pig, goat, or a primate.In the preferred embodiment, the subject is a human.

Design and Selection of iRNA Agents

As used herein, “disorders associated with alpha-ENaC expression” refersto any biological or pathological state that (1) is mediated at least inpart by the presence of alpha-ENaC and (2) whose outcome can be affectedby reducing the level of the alpha-ENaC present. Specific disordersassociated with alpha-ENaC expression are noted below.

The present invention is based on the design, synthesis and generationof iRNA agents that target alpha-ENaC and the demonstration of silencingof the alpha-ENaC gene in vitro in cultured cells after incubation withan iRNA agent, and the resulting protective effect towards alpha-ENaCmediated disorders.

An iRNA agent can be rationally designed based on sequence informationand desired characteristics. For example, an iRNA agent can be designedaccording to the relative melting temperature of the candidate duplex.Generally, the duplex should have a lower melting temperature at the 5′end of the antisense strand than at the 3′ end of the antisense strand.

The present invention provides compositions containing siRNA(s) and orshRNA(s) targeted to one or more alpha-ENaC transcripts.

For any particular gene target that is selected, the design of siRNAs orshRNAs for use in accordance with the present invention will preferablyfollow certain guidelines. Also, in many cases, the agent that isdelivered to a cell according to the present invention may undergo oneor more processing steps before becoming an active suppressing agent(see below for further discussion); in such cases, those of ordinaryskill in the art will appreciate that the relevant agent will preferablybe designed to include sequences that may be necessary for itsprocessing.

Diseases mediated by dysfunction of the epithelial sodium channel,include diseases associated with the regulation of fluid volumes acrossepithelial membranes. For example, the volume of airway surface liquidis a key regulator of mucociliary clearance and the maintenance of lunghealth. The blockade of the epithelial sodium channel will promote fluidaccumulation on the mucosal side of the airway epithelium therebypromoting mucus clearance and preventing the accumulation of mucus andsputum in respiratory tissues (including lung airways). Such diseasesinclude respiratory diseases, such as cystic fibrosis, primary ciliarydyskinesia, chronic bronchitis, chronic obstructive pulmonary disease(COPD), asthma, respiratory tract infections (acute and chronic; viraland bacterial) and lung carcinoma. Diseases mediated by blockade of theepithelial sodium channel also include diseases other than respiratorydiseases that are associated with abnormal fluid regulation across anepithelium, perhaps involving abnormal physiology of the protectivesurface liquids on their surface, e.g., xerostomia (cry mouth) orkeratoconjunctivitis sire (dry eye). Furthermore, blockade of theepithelial sodium channel in the kidney could be used to promotediuresis and thereby induce a hypotensive effect.

Treatment in accordance with the invention may be symptomatic orprophylactic.

Asthma includes both intrinsic (non-allergic) asthma and extrinsic(allergic) asthma, mild asthma, moderate asthma, severe asthma,bronchitic asthma, exercise-induced asthma, occupational asthma andasthma induced following bacterial infection. Treatment of asthma isalso to be understood as embracing treatment of subjects, e.g., of lessthan 4 or 5 years of age, exhibiting wheezing symptoms and diagnosed ordiagnosable as “wheezy infants”, an established patient category ofmajor medical concern and now often identified as incipient orearly-phase asthmatics. (For convenience this particular asthmaticcondition is referred to as “wheezy-infant syndrome”.)

Prophylactic efficacy in the treatment of asthma will be evidenced byreduced frequency or severity of symptomatic attack, e.g., of acuteasthmatic or bronchoconstrictor attack, improvement in lung function orimproved airways hyperreactivity. It may further be evidenced by reducedrequirement for other, symptomatic therapy, i.e., therapy for orintended to restrict or abort symptomatic attack when it occurs, e.g.,anti-inflammatory (e.g., corticosteroid) or bronchodilatory.Prophylactic benefit in asthma may, in particular, be apparent insubjects prone to “morning dipping”. “Morning dipping” is a recognizedasthmatic syndrome, common to a substantial percentage of asthmatics andcharacterized by asthma attack, e.g., between the hours of about 4-6 am,i.e., at a time normally substantially distant from any previouslyadministered symptomatic asthma therapy.

Chronic obstructive pulmonary disease includes chronic bronchitis ordyspnea associated therewith, emphysema, as well as exacerbation ofairways hyperreactivity consequent to other drug therapy, in particular,other inhaled drug therapy. The invention is also applicable to thetreatment of bronchitis of whatever type or genesis including, e.g.,acute, arachidic, catarrhal, croupus, chronic or phthinoid bronchitis.

Based on the results shown herein, the present invention provides iRNAagents that reduce alpha-ENaC expression in cultured cells and in asubject, e.g. a mammalian, for example a human. Tables 1A-1D provideexemplary iRNA agents targeting alpha-ENaC, based on the standardnomenclature abbreviations given in Table A.

Table 1A, Seq Id No.s 305-608, Table 1B and Table 1D, Seq Id No.s1519-1644 list siRNAs that do not comprise nucleotide modificationsexcept for one phosphorothioate linkage between the 3′-terminal and thepenultimate thymidines. The remaining Seq Ids in Tables 1A-1D listssiRNAs wherein all nucleotides comprising pyrimidine bases are2′-O-methyl-modified nucleotides in the sense strand, and all uridinesin a sequence context of 5′-ua-3′ as well as all cytidines in a sequencecontext of or 5′-ca-3′ are 2′-O-methyl-modified nucleotides in theantisense strand.

Based on these results, the invention specifically provides an iRNAagent that includes a sense strand having at least 15 contiguousnucleotides of the sense strand sequences of the agents provided inTables 1A-1D, and an antisense strand having at least 15 contiguousnucleotides of the antisense sequences of the agents provided in Tables1A-1D.

The iRNA agents shown in Tables 1A-1D are composed of two strands of 19nucleotides in length which are complementary or identical to the targetsequence, plus a 3′-TT overhang. The present invention provides agentsthat comprise at least 15, or at least 16, 17, or 18, or 19 contiguousnucleotides from these sequences. However, while these lengths maypotentially be optimal, the iRNA agents are not meant to be limited tothese lengths. The skilled person is well aware that shorter or longeriRNA agents may be similarly effective, since, within certain lengthranges, the efficacy is rather a function of the nucleotide sequencethan strand length. For example, Yang, et al., PNAS 99:9942-9947 (2002),demonstrated similar efficacies for iRNA agents of lengths between 21and 30 base pairs. Others have shown effective silencing of genes byiRNA agents down to a length of approx. 15 base pairs (Byrom, et al.,“Inducing RNAi with siRNA Cocktails Generated by RNase III” Tech Notes10(1), Ambion, Inc., Austin, Tex.).

Therefore, it is possible and contemplated by the instant invention toselect from the sequences provided in Tables 1A-1D a partial sequence ofbetween 15 to 19 nucleotides for the generation of an iRNA agent derivedfrom one of the sequences provided in Tables 1A-1D. Alternatively, onemay add one or several nucleotides to one of the sequences provided inTables 1A-1D, or an agent comprising 15 contiguous nucleotides from oneof these agents, preferably, but not necessarily, in such a fashion thatthe added nucleotides are complementary to the respective sequence ofthe target gene, e.g., alpha-ENaC. For example, the first 15 nucleotidesfrom one of the agents can be combined with the 8 nucleotides found 5′to these sequence in alpha-ENaC mRNA to obtain an agent with 23nucleotides in the sense and antisense strands. All such derived iRNAagents are included in the iRNA agents of the present invention,provided they essentially retain the ability to inhibit alpha-ENaCreplication in cultured human cells.

The antisense strand of an iRNA agent should be equal to or at least,14, 15, 16, 17, 18, 19, 25, 29, 40, or 50 nucleotides in length. Itshould be equal to or less than 60, 50, 40, or 30, nucleotides inlength. Preferred ranges are 15-30, 17 to 25, 19 to 23, and 19 to 21nucleotides in length.

The sense strand of an iRNA agent should be equal to or at least 14, 15,16 17, 18, 19, 25, 29, 40, or 50 nucleotides in length. It should beequal to or less than 60, 50, 40, or 30 nucleotides in length. Preferredranges are 15-30, 17 to 25, 19 to 23, and 19 to 21 nucleotides inlength.

The double stranded portion of an iRNA agent should be equal to or atleast, 15, 16 17, 18, 19, 20, 21, 22, 23, 24, 25, 29, 40, or 50nucleotide pairs in length. It should be equal to or less than 60, 50,40, or 30 nucleotides pairs in length. Preferred ranges are 15-30, 17 to25, 19 to 23, and 19 to 21 nucleotides pairs in length.

Generally, the iRNA agents of the instant invention include a region ofsufficient complementarity to the alpha-ENaC mRNA, and are of sufficientlength in terms of nucleotides, that the iRNA agent, or a fragmentthereof, can mediate down regulation of the alpha-ENaC gene. It is notnecessary that there be perfect complementarity between the iRNA agentand the target gene, but the correspondence must be sufficient to enablethe iRNA agent, or a cleavage product thereof, to direct sequencespecific silencing, e.g., by RNAi cleavage of an alpha-ENaC mRNA.

Therefore, the iRNA agents of the instant invention include agentscomprising a sense strand and antisense strand each comprising asequence of at least 16, 17 or 18 nucleotides which is essentiallyidentical, as defined below, to one of the sequences of Tables 1A-1D,except that not more than 1, 2 or 3 nucleotides per strand,respectively, have been substituted by other nucleotides (e.g. adenosinereplaced by uracil), while essentially retaining the ability to inhibitalpha-ENaC expression in cultured human cells. These agents willtherefore possess at least 15 nucleotides identical to one of thesequences of Tables 1A-1D, but 1, 2 or 3 base mismatches with respect toeither the target alpha-ENaC sequence or between the sense and antisensestrand are introduced. Mismatches to the target alpha-ENaC RNA sequence,particularly in the antisense strand, are most tolerated in the terminalregions and if present are preferably in a terminal region or regions,e.g., within 6, 5, 4, or 3 nucleotides of a 5′ and or 3′ terminus, mostpreferably within 6, 5, 4, or 3 nucleotides of the 5′-terminus of thesense strand or the 3′-terminus of the antisense strand. The sensestrand need only be sufficiently complementary with the antisense strandto maintain the overall double stranded character of the molecule.

It is preferred that the sense and antisense strands be chosen such thatthe iRNA agent includes a single strand or unpaired region at one orboth ends of the molecule. Thus, an iRNA agent contains sense andantisense strands, preferably paired to contain an overhang, e.g., oneor two 5′ or 3′ overhangs but preferably a 3′ overhang of 2-3nucleotides. Most embodiments will have a 3′ overhang. Preferred siRNAagents will have single-stranded overhangs, preferably 3′ overhangs, of1 to 4, or preferably 2 or 3 nucleotides, in length, at one or both endsof the iRNA agent. The overhangs can be the result of one strand beinglonger than the other, or the result of two strands of the same lengthbeing staggered. The unpaired nucleotides forming the overhang can beribonucleotides, or they can be deoxyribonucleotides, preferablythymidine. 5′-ends are preferably phosphorylated, or they may beunphosphorylated.

Preferred lengths for the duplexed region are between 15 and 30, mostpreferably 18, 19, 20, 21, 22, and 23 nucleotides in length, e.g., inthe siRNA agent range discussed above. siRNA agents can resemble inlength and structure the natural Dicer processed products from longdsRNAs. Embodiments in which the two strands of the siRNA agent arelinked, e.g., covalently linked, are also included. Hairpin, or othersingle strand structures which provide the required double strandedregion, and preferably a 3′ overhang are also within the invention.

Evaluation of Candidate iRNA Agents

As noted above, the present invention provides a system for identifyingsiRNAs that are useful as inhibitors of alpha-ENaC. Since, as notedabove, shRNAs are processed intracellularly to produce siRNAs havingduplex portions with the same sequence as the stem structure of theshRNA, the system is equally useful for identifying shRNAs that areuseful as inhibitors of alpha-ENaC. For purposes of description thissection will refer to siRNAs, but the system also encompassescorresponding shRNAs. Specifically, the present invention demonstratesthe successful preparation of siRNAs targeted to inhibit alpha-ENaCactivity. The techniques and reagents described herein can readily beapplied to design potential new siRNAs, targeted to other genes or generegions, and tested for their activity in inhibiting alpha-ENaC asdiscussed herein.

In various embodiments of the invention potential alpha-ENaC inhibitorscan be tested for suppression of endogenous alpha-ENaC expression byintroducing candidate siRNA(s) into cells (e.g., by exogenousadministration or by introducing a vector or construct that directsendogenous synthesis of siRNA into the cell), or in laboratory animalsby pulmonary or nasal administration. Alternately, potential alpha-ENaCinhibitors can be tested in vitro by transient co-transfection ofcandidate siRNA(s) together with an alpha-ENaC-expression plasmid. Theability of the candidate siRNA(s) to reduce target transcript levels andor to inhibit or suppress one or more aspects or features of alpha-ENaCactivity such as epithelial potential difference or airway surface fluidabsorption is then assessed.

Cells or laboratory animals to which inventive siRNA compositions havebeen delivered (test cells/animals) may be compared with similar orcomparable cells or laboratory animals that have not received theinventive composition (control cells/animals, e.g., cells/animals thathave received either no siRNA or a control siRNA such as an siRNAtargeted to a non-endogenous transcript such as green fluorescentprotein (GFP)). The ion transport phenotype of the test cells/animalscan be compared with the phenotype of control cells/animals, providingthat the inventive siRNA share sequence cross-reactivity with the testcell type/species. Production of alpha-ENaC protein and short circuitcurrent (in vitro or ex vivo) may be compared in the test cells/animalsrelative to the control cells/animals. Other indicia of alpha-ENaCactivity, including ex vivo epithelial potential difference or in vivomucocilliary clearance or whole body magnetic resonance imaging (MRI),can be similarly compared. Generally, test cells/animals and controlcells/animals would be from the same species and, for cells, of similaror identical cell type. For example, cells from the same cell line couldbe compared. When the test cell is a primary cell, typically the controlcell would also be a primary cell.

For example, the ability of a candidate siRNA to inhibit alpha-ENaCactivity may conveniently be determined by (i) delivering the candidatesiRNA to cells (ii) assessing the expression levels of alpha-ENaC mRNArelative to an endogenously expressed control gene (iii) comparing theamiloride-sensitive current in an in vitro cell model produced in thepresence of the siRNA with the amount produced in the absence of thesiRNA. This latter assay may be used to test siRNAs that target anytarget transcript that may influence alpha-ENaC activity indirectly andis not limited to siRNAs that target the transcripts that encode theENaC channel subunits.

The ability of a candidate siRNA to reduce the level of the targettranscript may be assessed by measuring the amount of the targettranscript using, for example, Northern blots, nuclease protectionassays, probe hybridization, reverse transcription (RT)-PCR, real-timeRT-PCR, microarray analysis, etc. The ability of a candidate siRNA toinhibit production of a polypeptide encoded by the target transcript(either at the transcriptional or post-transcriptional level) may bemeasured using a variety of antibody-based approaches including, but notlimited to, Western blots, immunoassays, ELISA, flow cytometry, proteinmicroarrays, etc. In general, any method of measuring the amount ofeither the target transcript or a polypeptide encoded by the targettranscript may be used.

In general, certain preferred alpha-ENaC iRNA inhibitors reduce thetarget transcript level at least about 2 fold, preferably at least about4 fold, more preferably at least about 8 fold, at least about 16 fold,at least about 64 fold or to an even greater degree relative to thelevel that would be present in the absence of the inhibitor (e.g., in acomparable control cell lacking the inhibitor). In general, certainpreferred alpha-ENaC iRNA inhibitors inhibit ENaC channel activity, sothat the activity is lower in a cell containing the inhibitor than in acontrol cell not containing the inhibitor by at least about 2 fold,preferably at least about 4 fold, more preferably at least about 8 fold,at least about 16 fold, at least about 64 fold, at least about 100 fold,at least about 200 fold, or to an even greater degree.

Certain preferred alpha-ENaC iRNA inhibitors inhibit ENaC channelactivity for at least 12 hours, at least 24 hours, at least 36 hours, atleast 48 hours, at least 60 hours, at least 72 hours, at least 96 hours,at least 120 hours, at least 144 hours or at least 168 hours followingadministration of the siRNA and infection of the cells. Certainpreferred alpha-ENaC inhibitors prevent (i.e., reduce to undetectablelevels) or significantly reduce alpha-ENaC activity for at least 24hours, at least 36 hours, at least 48 hours, or at least 60 hoursfollowing administration of the siRNA. According to various embodimentsof the invention a significant reduction in alpha-ENaC activity is areduction to less than approximately 90% of the level that would occurin the absence of the siRNA, a reduction to less than approximately 75%of the level that would occur in the absence of the siRNA, a reductionto less than approximately 50% of the level that would occur in theabsence of the siRNA, a reduction to less than approximately 25% of thelevel that would occur in the absence of the siRNA, or a reduction toless than approximately 10% of the level that would occur in the absenceof the siRNA. Reduction in alpha-ENaC activity may be measured using anysuitable method including, but not limited to, short circuit currentmeasurement of amiloride sensitivity in vitro, epithelial potentialdifference ex vivo or in vivo mucocilliary clearance or whole body/lungMRI.

Stability Testing, Modification, and Retesting of iRNA Agents

A candidate iRNA agent can be evaluated with respect to stability, e.g.,its susceptibility to cleavage by an endonuclease or exonuclease, suchas when the iRNA agent is introduced into the body of a subject. Methodscan be employed to identify sites that are susceptible to modification,particularly cleavage, e.g., cleavage by a component found in the bodyof a subject. Such methods may include the isolation and identificationof most abundant fragments formed by degradation of the candidate iRNAagent after its incubation with isolated biological media in vitro, e.g.serum, plasma, sputum, cerebrospinal fluid, or cell or tissuehomogenates, or after contacting a subject with the candidate iRNA agentin vivo, thereby identifying sites prone to cleavage. Such methods are,for example, without limitation, in International Patent ApplicationPublication No. WO2005115481, filed on May 27, 2005.

When sites susceptible to cleavage are identified, a further iRNA agentcan be designed and or synthesized wherein the potential cleavage siteis made resistant to cleavage, e.g. by introduction of a 2′-modificationon the site of cleavage, e.g. a 2′-O-methyl group. This further iRNAagent can be retested for stability, and this process may be iterateduntil an iRNA agent is found exhibiting the desired stability.

In Vivo Testing

An iRNA agent identified as being capable of inhibiting alpha-ENaC geneexpression can be tested for functionality in vivo in an animal model(e.g., in a mammal, such as in mouse, rat, guinea-pig or primate). Forexample, the iRNA agent can be administered to an animal, and the iRNAagent evaluated with respect to its biodistribution, stability, and itsability to inhibit alpha-ENaC expression or modulate a biological orpathological process mediated at least in part by alpha-ENaC.

The iRNA agent can be administered directly to the target tissue, suchas by injection, or the iRNA agent can be administered to the animalmodel in the same manner that it would be administered to a human.Preferably, the iRNA agent is delivered to the subject's airways, suchas by intranasal, inhaled or intratracheal administration.

The iRNA agent can also be evaluated for its intracellular distribution.The evaluation can include determining whether the iRNA agent was takenup into the cell. The evaluation can also include determining thestability (e.g., the half-life) of the iRNA agent. Evaluation of an iRNAagent in vivo can be facilitated by use of an iRNA agent conjugated to atraceable marker (e.g., a fluorescent marker such as fluorescein; aradioactive label, such as ³⁵S, ³²P, ³³P, or ³H; gold particles; orantigen particles for immunohistochemistry).

The iRNA agent can be evaluated with respect to its ability to downregulate alpha-alpha-ENaC expression. Levels of alpha-ENaC geneexpression in vivo can be measured, for example, by in situhybridization, or by the isolation of RNA from tissue prior to andfollowing exposure to the iRNA agent. Where the animal needs to besacrificed in order to harvest the tissue, an untreated control animalwill serve for comparison. alpha-ENaC RNA can be detected by any desiredmethod, including but not limited to RT-PCR, northern blot, branched-DNAassay, or RNAase protection assay. Alternatively, or additionally,alpha-ENaC gene expression can be monitored by performing western blotanalysis or immunostaining on tissue extracts treated with the iRNAagent.

Potential alpha-ENaC inhibitors can be tested using any variety ofanimal models that have been developed. Compositions comprisingcandidate siRNA(s), constructs or vectors capable of directing synthesisof such siRNAs within a host cell, or cells engineered or manipulated tocontain candidate siRNAs may be administered to an animal. The abilityof the composition to suppress alpha-ENaC expression and or to modifyENaC-dependent phenotypes and/or lessen their severity relative toanimals that have not received the potential alpha-ENaC inhibitor isassessed. Such models include, but are not limited to, murine, rat,guinea pig, sheep and non-human primate models for ENaC-dependentphenotypes, all of which are known in the art and are used for testingthe efficacy of potential alpha-ENaC therapeutics.

Utilising the systems invented for identifying candidate therapeuticsiRNA agents, suitable therapeutic agents are selected from Duplexidentifiers ND-8302, ND-8332, ND-8348, ND-8356, ND-8357, ND-8373,ND-8381, ND-8396, ND-8450 and ND-8453, more suitably selected fromND-8356, ND-8357 and ND-8396.

iRNA Chemistry

Described herein are isolated iRNA agents, e.g., ds RNA agents thatmediate RNAi to inhibit expression of the alpha-ENaC gene.

RNA agents discussed herein include otherwise unmodified RNA as well asRNA which has been modified, e.g., to improve efficacy, and polymers ofnucleoside surrogates. Unmodified RNA refers to a molecule in which thecomponents of the nucleic acid, namely sugars, bases, and phosphatemoieties, are the same or essentially the same as that which occur innature, preferably as occur naturally in the human body. The art hasreferred to rare or unusual, but naturally occurring, RNAs as modifiedRNAs, see, e.g., Limbach et al. Nucleic Acids Res. 22: 2183-2196, 1994.Such rare or unusual RNAs, often termed modified RNAs (apparentlybecause they are typically the result of a post-transcriptionalmodification) are within the term unmodified RNA, as used herein.Modified RNA as used herein refers to a molecule in which one or more ofthe components of the nucleic acid, namely sugars, bases, and phosphatemoieties, are different from that which occurs in nature, preferablydifferent from that which occurs in the human body. While they arereferred to as modified “RNAs,” they will of course, because of themodification, include molecules which are not RNAs. Nucleosidesurrogates are molecules in which the ribophosphate backbone is replacedwith a non-ribophosphate construct that allows the bases to thepresented in the correct spatial relationship such that hybridization issubstantially similar to what is seen with a ribophosphate backbone,e.g., non-charged mimics of the ribophosphate backbone. Examples of theabove are discussed herein.

Modifications described herein can be incorporated into anydouble-stranded RNA and RNA-like molecule described herein, e.g., aniRNA agent. It may be desirable to modify one or both of the antisenseand sense strands of an iRNA agent. As nucleic acids are polymers ofsubunits or monomers, many of the modifications described below occur ata position which is repeated within a nucleic acid, e.g., a modificationof a base, or a phosphate moiety, or the non-linking oxygen of aphosphate moiety. In some cases the modification will occur at all ofthe subject positions in the nucleic acid but in many, and in fact inmost, cases it will not. By way of example, a modification may onlyoccur at a 3′ or 5′ terminal position, may only occur in a terminalregion, e.g. at a position on a terminal nucleotide or in the last 2, 3,4, 5, or 10 nucleotides of a strand. A modification may occur in adouble strand region, a single strand region, or in both. E.g., aphosphorothioate modification at a non-linking O position may only occurat one or both termini, may only occur in a terminal regions, e.g., at aposition on a terminal nucleotide or in the last 2, 3, 4, 5, or 10nucleotides of a strand, or may occur in double strand and single strandregions, particularly at termini. Similarly, a modification may occur onthe sense strand, antisense strand, or both. In some cases, the senseand antisense strand will have the same modifications or the same classof modifications, but in other cases the sense and antisense strand willhave different modifications, e.g., in some cases it may be desirable tomodify only one strand, e.g. the sense strand.

Two prime objectives for the introduction of modifications into iRNAagents is their stabilization towards degradation in biologicalenvironments and the improvement of pharmacological properties, e.g.pharmacodynamic properties, which are further discussed below. Othersuitable modifications to a sugar, base, or backbone of an iRNA agentare described in PCT Application No. PCT/US2004/01193, filed Jan. 16,2004. An iRNA agent can include a non-naturally occurring base, such asthe bases described in PCT Application No. PCT/US2004/011822, filed Apr.16, 2004. An iRNA agent can include a non-naturally occurring sugar,such as a non-carbohydrate cyclic carrier molecule. Exemplary featuresof non-naturally occurring sugars for use in iRNA agents are describedin PCT Application No. PCT US2004/11829, filed Apr. 16, 2003.

An iRNA agent can include an internucleotide linkage (e.g., the chiralphosphorothioate linkage) useful for increasing nuclease resistance. Inaddition, or in the alternative, an iRNA agent can include a ribosemimic for increased nuclease resistance. Exemplary internucleotidelinkages and ribose mimics for increased nuclease resistance aredescribed in PCT Application No. PCT/US2004/07070, filed on Mar. 8,2004.

An iRNA agent can include ligand-conjugated monomer subunits andmonomers for oligonucleotide synthesis. Exemplary monomers are describedin U.S. application Ser. No. 10/916,185, filed on Aug. 10, 2004.

An iRNA agent can have a ZXY structure, such as is described in PCTApplication No. PCT/US2004/07070, filed on Mar. 8, 2004.

An iRNA agent can be complexed with an amphipathic moiety. Exemplaryamphipathic moieties for use with iRNA agents are described in PCTApplication No. PCT/US2004/07070, filed on Mar. 8, 2004.

In another embodiment, the iRNA agent can be complexed to a deliveryagent that features a modular complex. The complex can include a carrieragent linked to one or more of (preferably two or more, more preferablyall three of): (a) a condensing agent (e.g., an agent capable ofattracting, e.g., binding, a nucleic acid, e.g., through ionic orelectrostatic interactions); (b) a fusogenic agent (e.g., an agentcapable of fusing and or being transported through a cell membrane); and(c) a targeting group, e.g., a cell or tissue targeting agent, e.g., alectin, glycoprotein, lipid or protein, e.g., an antibody, that binds toa specified cell type. iRNA agents complexed to a delivery agent aredescribed in PCT Application No. PCT US2004/07070, filed on Mar. 8,2004.

An iRNA agent can have non-canonical pairings, such as between the senseand antisense sequences of the iRNA duplex. Exemplary features ofnon-canonical iRNA agents are described in PCT Application No. PCTUS2004/07070, filed on Mar. 8, 2004.

Enhanced Nuclease Resistance

An iRNA agent, e.g., an iRNA agent that targets alpha-ENaC, can haveenhanced resistance to nucleases.

One way to increase resistance is to identify cleavage sites and modifysuch sites to inhibit cleavage, as described in U.S. Application No.60/559,917, filed on May 4, 2004. For example, the dinucleotides5′-ua-3′,5′-ca-3′, 5′-ug-3′,5′-uu-3′, or 5′-cc-3′ can serve as cleavagesites. In certain embodiments, all the pyrimidines of an iRNA agentcarry a 2′-modification in either the sense strand, the antisensestrand, or both strands, and the iRNA agent therefore has enhancedresistance to endonucleases. Enhanced nuclease resistance can also beachieved by modifying the 5′ nucleotide, resulting, for example, in atleast one 5′-uridine-adenine-3′ (5′-ua-3′) dinucleotide wherein theuridine is a 2′-modified nucleotide; at least one 5′-cytidine-adenine-3′(5′-ca-3′) dinucleotide, wherein the 5′-cytidine is a 2′-modifiednucleotide; at least one 5′-uridine-guanine-3′ (5′-ug-3′) dinucleotide,wherein the 5′-uridine is a 2′-modified nucleotide; at least one5′-uridine-uridine-3′ (5′-uu-3′) dinucleotide, wherein the 5′-uridine isa 2′-modified nucleotide; or at least one 5′-cytidine-cytidine-3′(5′-cc-3′) dinucleotide, wherein the 5′-cytidine is a 2′-modifiednucleotide, as described in International Application No. PCTUS2005/018931, filed on May 27, 2005. The iRNA agent can include atleast 2, at least 3, at least 4 or at least 5 of such dinucleotides. Ina particularly preferred embodiment, the 5′ nucleotide in alloccurrences of the sequence motifs 5′-ua-3′ and 5′-ca-3′ in either thesense strand, the antisense strand, or both strands is a modifiednucleotide. Preferably, the 5′ nucleotide in all occurrences of thesequence motifs 5′-ua-3′,5′-ca-3′ and 5′-ug-3′ in either the sensestrand, the antisense strand, or both strands is a modified nucleotide.More preferably, all pyrimidine nucleotides in the sense strand aremodified nucleotides, and the 5′ nucleotide in all occurrences of thesequence motifs 5′-ua-3′ and 5′-ca-3′ in the antisense strand aremodified nucleotides, or where the antisense strand does compriseneither of a 5′-ua-3′ and a 5′-ca-3′ motif, in all occurrences of thesequence motif 5′-ug-3′.

Preferably, the 2′-modified nucleotides include, for example, a2′-modified ribose unit, e.g., the 2′-hydroxyl group (OH) can bemodified or replaced with a number of different “oxy” or “deoxy”substituents.

Examples of “oxy”-2′ hydroxyl group modifications include alkoxy oraryloxy (OR, e.g., R═H, alkyl, cycloalkyl, aryl, aralkyl, heteroaryl orsugar); polyethyleneglycols (PEG), O(CH₂CH₂O)_(n)CH₂CH₂ OR; “locked”nucleic acids (LNA) in which the 2′ hydroxyl is connected, e.g., by amethylene bridge, to the 4′ carbon of the same ribose sugar; O-AMINE andaminoalkoxy, O(CH₂)_(n)AMINE, (e.g., AMINE=NH₂; alkylamino,dialkylamino, heterocyclyl amino, arylamino, diaryl amino, heteroarylamino, or diheteroaryl amino, ethylene diamine, polyamino). It isnoteworthy that oligonucleotides containing only the methoxyethyl group(MOE), (OCH₂CH₂OCH₃, a PEG derivative), exhibit nuclease stabilitiescomparable to those modified with the robust phosphorothioatemodification.

“Deoxy” modifications include hydrogen (i.e. deoxyribose sugars, whichare of particular relevance to the overhang portions of partially dsRNA); halo (e.g., fluoro); amino (e.g. NH₂; alkylamino, dialkylamino,heterocyclyl, arylamino, diaryl amino, heteroaryl amino, diheteroarylamino, or amino acid); NH(CH₂CH₂NH)_(n)CH₂CH₂-AMINE (AMINE=NH₂;alkylamino, dialkylamino, heterocyclyl amino, arylamino, diaryl amino,heteroaryl amino, or diheteroaryl amino), —NHC(O)R(R=alkyl, cycloalkyl,aryl, aralkyl, heteroaryl or sugar), cyano; mercapto; alkyl-thio-alkyl;thioalkoxy; and alkyl, cycloalkyl, aryl, alkenyl and alkynyl, which maybe optionally substituted with e.g., an amino functionality.

Preferred substitutents are 2′-methoxyethyl, 2′-OCH₃, 2′-O-allyl,2′-C-allyl, and 2′-fluoro.

The inclusion of furanose sugars in the oligonucleotide backbone canalso decrease endonucleolytic cleavage. An iRNA agent can be furthermodified by including a 3′ cationic group, or by inverting thenucleoside at the 3′-terminus with a 3′-3′ linkage. In anotheralternative, the 3′-terminus can be blocked with an aminoalkyl group,e.g., a 3′ C5-aminoalkyl dT. Other 3′ conjugates can inhibit 3′-5′exonucleolytic cleavage. While not being bound by theory, a 3′conjugate, such as naproxen or ibuprofen, may inhibit exonucleolyticcleavage by sterically blocking the exonuclease from binding to the3′-end of oligonucleotide. Even small alkyl chains, aryl groups, orheterocyclic conjugates or modified sugars (D-ribose, deoxyribose,glucose etc.) can block 3′-5′-exonucleases.

Nucleolytic cleavage can also be inhibited by the introduction ofphosphate linker modifications, e.g., phosphorothioate linkages. Thus,preferred iRNA agents include nucleotide dimers enriched or pure for aparticular chiral form of a modified phosphate group containing aheteroatom at a nonbridging position normally occupied by oxygen. Theheteroatom can be S, Se, Nr₂, or Br₃. When the heteroatom is S, enrichedor chirally pure Sp linkage is preferred. Enriched means at least 70,80, 90, 95, or 99% of the preferred form. Modified phosphate linkagesare particularly efficient in inhibiting exonucleolytic cleavage whenintroduced near the 5′- or 3′-terminal positions, and preferably the5′-terminal positions, of an iRNA agent.

5′ conjugates can also inhibit 5′-3′ exonucleolytic cleavage. While notbeing bound by theory, a 5′ conjugate, such as naproxen or ibuprofen,may inhibit exonucleolytic cleavage by sterically blocking theexonuclease from binding to the 5′-end of oligonucleotide. Even smallalkyl chains, aryl groups, or heterocyclic conjugates or modified sugars(D-ribose, deoxyribose, glucose etc.) can block 3′-5′-exonucleases.

An iRNA agent can have increased resistance to nucleases when a duplexediRNA agent includes a single-stranded nucleotide overhang on at leastone end. In preferred embodiments, the nucleotide overhang includes 1 to4, preferably 2 to 3, unpaired nucleotides. In a preferred embodiment,the unpaired nucleotide of the single-stranded overhang that is directlyadjacent to the terminal nucleotide pair contains a purine base, and theterminal nucleotide pair is a G-C pair, or at least two of the last fourcomplementary nucleotide pairs are G-C pairs. In further embodiments,the nucleotide overhang may have 1 or 2 unpaired nucleotides, and in anexemplary embodiment the nucleotide overhang is 5′-gc-3′. In preferredembodiments, the nucleotide overhang is on the 3′-end of the antisensestrand. In one embodiment, the iRNA agent includes the motif 5′-cgc-3′on the 3′-end of the antisense strand, such that a 2-nt overhang5′-gc-3′ is formed.

Thus, an iRNA agent can include modifications so as to inhibitdegradation, e.g., by nucleases, e.g., endonucleases or exonucleases,found in the body of a subject. These monomers are referred to herein asNRMs, or Nuclease Resistance promoting Monomers, the correspondingmodifications as NRM modifications. In many cases these modificationswill modulate other properties of the iRNA agent as well, e.g., theability to interact with a protein, e.g., a transport protein, e.g.,serum albumin, or a member of the RISC, or the ability of the first andsecond sequences to form a duplex with one another or to form a duplexwith another sequence, e.g., a target molecule.

One or more different NW modifications can be introduced into an iRNAagent or into a sequence of an iRNA agent. An NRM modification can beused more than once in a sequence or in an iRNA agent.

NR modifications include some which can be placed only at the terminusand others which can go at any position. Some NR modifications caninhibit hybridization so it is preferable to use them only in terminalregions, and preferable to not use them at the cleavage site or in thecleavage region of a sequence which targets a subject sequence or gene,particularly on the antisense strand. They can be used anywhere in asense strand, provided that sufficient hybridization between the twostrands of the ds iRNA agent is maintained. In some embodiments it isdesirable to put the NRM at the cleavage site or in the cleavage regionof a sense strand, as it can minimize off-target silencing.

In most cases, NRM modifications will be distributed differentlydepending on whether they are comprised on a sense or antisense strand.If on an antisense strand, modifications which interfere with or inhibitendonuclease cleavage should not be inserted in the region which issubject to RISC mediated cleavage, e.g., the cleavage site or thecleavage region (As described in Elbashir et al., 2001, Genes and Dev.15: 188, hereby incorporated by reference). Cleavage of the targetoccurs about in the middle of a 20 or 21 nt antisense strand, or about10 or 11 nucleotides upstream of the first nucleotide on the target mRNAwhich is complementary to the antisense strand. As used herein cleavagesite refers to the nucleotides on either side of the cleavage site, onthe target or on the iRNA agent strand which hybridizes to it. Cleavageregion means the nucleotides within 1, 2, or 3 nucleotides of thecleavages site, in either direction.

Such modifications can be introduced into the terminal regions, e.g., atthe terminal position or with 2, 3, 4, or 5 positions of the terminus,of a sense or antisense strand.

Tethered Ligands

The properties of an iRNA agent, including its pharmacologicalproperties, can be influenced and tailored, for example, by theintroduction of ligands, e.g. tethered ligands. In addition,pharmacological properties of an iRNA agent can be improved byincorporating a ligand in a formulation of the iRNA agent when the iRNAagent either has or does have a tethered ligand.

A wide variety of entities, e.g., ligands, can be tethered to an iRNAagent or used as formulation conjugate or additive, e.g., to the carrierof a ligand-conjugated monomer subunit. Examples are described below inthe context of a ligand-conjugated monomer subunit but that is onlypreferred, entities can be coupled at other points to an iRNA agent.

Preferred moieties are ligands, which are coupled, preferablycovalently, either directly or indirectly, via an intervening tether tothe carrier. In preferred embodiments, the ligand is attached to thecarrier via an intervening tether. The ligand or tethered ligand may bepresent on the ligand-conjugated monomer when the ligand-conjugatedmonomer is incorporated into the growing strand. In some embodiments,the ligand may be incorporated into a “precursor” ligand-conjugatedmonomer subunit after a “precursor” ligand-conjugated monomer subunithas been incorporated into the growing strand. For example, a monomerhaving, e.g., an amino-terminated tether, e.g., TAP—(CH₂)_(n)NH₂ may beincorporated into a growing sense or antisense strand. In a subsequentoperation, i.e., after incorporation of the precursor monomer subunitinto the strand, a ligand having an electrophilic group, e.g., apentafluorophenyl ester or aldehyde group, can subsequently be attachedto the precursor ligand-conjugated monomer by coupling the electrophilicgroup of the ligand with the terminal nucleophilic group of theprecursor ligand-conjugated monomer subunit tether.

In preferred embodiments, a ligand alters the distribution, targeting orlifetime of an iRNA agent into which it is incorporated. In preferredembodiments a ligand provides an enhanced affinity for a selectedtarget, e.g., molecule, cell or cell type, compartment, e.g., a cellularor organ compartment, tissue, organ or region of the body, as, e.g.,compared to a species absent such a ligand.

Preferred ligands can improve transport, hybridization, and specificityproperties and may also improve nuclease resistance of the resultantnatural or modified oligoribonucleotide, or a polymeric moleculecomprising any combination of monomers described herein and/or naturalor modified ribonucleotides.

Ligands in general can include therapeutic modifiers, e.g., forenhancing uptake; diagnostic compounds or reporter groups e.g., formonitoring distribution; cross-linking agents; nuclease-resistanceconferring moieties; and natural or unusual nucleobases. Generalexamples include lipophilic molecules, lipids, lectins, steroids (e.g.,uvaol, hecigenin, diosgenin), terpenes (e.g., triterpenes, e.g.,sarsasapogenin, Friedelin, epifriedelanol derivatized lithocholic acid),vitamins, carbohydrates (e.g., a dextran, pullulan, chitin, chitosan,synthetic (eg Oligo Lactate 15-mer) and natural (eg low and mediummolecular weight) polymers, inulin, cyclodextrin or hyaluronic acid),proteins, protein binding agents, integrin targeting molecules,polycationics, peptides, polyamines, and peptide mimics. Other examplesinclude folic acid or epithelial cell receptor ligands, such astransferin.

The ligand may be a naturally occurring or recombinant or syntheticmolecule, such as a synthetic polymer, e.g., a synthetic polyamino acid.Examples of polyamino acids include polylysine (PLL), poly L-asparticacid, poly L-glutamic acid, styrene-maleic acid anhydride copolymer,poly(L-lactide-co-glycolied) copolymer, divinyl ether-maleic anhydridecopolymer, N-(2-hydroxypropyl)methacrylamide copolymer (HMPA),polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyurethane,poly(2-ethylacrylic acid), N-isopropylacrylamide polymers, orpolyphosphazine. Example of polyamines include: polyethylenimine,polylysine (PLL), spermine, spermidine, polyamine,pseudopeptide-polyamine, peptidomimetic polyamine, dendrimer polyanine,arginine, amidine, protamine, cationic moieties, e.g., cationic lipid,cationic porphyrin, quaternary salt of a polyamine, or an alpha helicalpeptide.

Ligands can also include targeting groups, e.g., a cell or tissuetargeting agent, e.g., a thyrotropin, melanotropin, surfactant proteinA, mucin carbohydrate, a glycosylated polyaminoacid, transferrin,bisphosphonate, polyglutamate, polyaspartate, or an Arg-Gly-Asp (RGD)peptide or RGD peptide mimetic.

Ligands can be proteins, e.g., glycoproteins, lipoproteins, e.g. lowdensity lipoprotein (LDL), or albumins, e.g. human serum albumin (HSA),or peptides, e.g., molecules having a specific affinity for a co-ligand,or antibodies e.g., an antibody, that binds to a specified cell typesuch as a cancer cell, endothelial cell, or bone cell. Ligands may alsoinclude hormones and hormone receptors. They can also includenon-peptidic species, such as cofactors, multivalent lactose,multivalent galactose, N-acetyl-galactosamine, N-acetyl-glucosamine,multivalent mannose, or multivalent fucose.

The ligand can be a substance, e.g, a drug, which can increase theuptake of the iRNA agent into the cell, for example, by disrupting thecell's cytoskeleton, e.g., by disrupting the cell's microtubules,microfilaments, and or intermediate filaments. The drug can be, forexample, taxon, vincristine, vinblastine, cytochalasin, nocodazole,japlakinolide, latrunculin A, phalloidin, swinholide A, indanocine,myoservin, tetracyclin.

In one aspect, the ligand is a lipid or lipid-based molecule. Such alipid or lipid-based molecule preferably binds a serum protein, e.g.,human serum albumin (HSA). An HSA binding ligand allows for distributionof the conjugate to a target tissue, e.g., liver tissue, includingparenchymal cells of the liver. Other molecules that can bind HSA canalso be used as ligands. For example, neproxin or aspirin can be used. Alipid or lipid-based ligand can (a) increase resistance to degradationof the conjugate, (b) increase targeting or transport into a target cellor cell membrane, and or (c) can be used to adjust binding to a serumprotein, e.g., HSA.

A lipid based ligand can be used to modulate, e.g., control the bindingof the conjugate to a target tissue. For example, a lipid or lipid-basedligand that binds to HSA more strongly will be less likely to betargeted to the kidney and therefore less likely to be cleared from thebody.

In a preferred embodiment, the lipid based ligand binds HSA. Preferably,it binds HSA with a sufficient affinity such that the conjugate will bepreferably distributed to a non-kidney tissue. However, it is preferredthat the affinity not be so strong that the HSA-ligand binding cannot bereversed.

In another aspect, the ligand is a moiety, e.g., a vitamin or nutrient,which is taken up by a target cell, e.g., a proliferating cell. Theseare particularly useful for treating disorders characterized by unwantedcell proliferation, e.g., of the malignant or non-malignant type, e.g.,cancer cells. Exemplary vitamins include vitamin A, E, and K. Otherexemplary vitamins include the B vitamins, e.g., folic acid, B12,riboflavin, biotin, pyridoxal or other vitamins or nutrients taken up bycancer cells.

In another aspect, the ligand is a cell-permeation agent, preferably ahelical cell-permeation agent. Preferably, the agent is amphipathic. Anexemplary agent is a peptide such as tat or antennapedia. If the agentis a peptide, it can be modified, including a peptidylmimetic,invertomers, non-peptide or pseudo-peptide linkages, and use of D-aminoacids. The helical agent is preferably an alpha-helical agent, whichpreferably has a lipophilic and a lipophobic phase. The cell permeationagent can be linked covalently to the iRNA agent or be part of aniRNA-peptide complex.

5′-Phosphate Modifications

In preferred embodiments, iRNA agents are 5′ phosphorylated or include aphosphoryl analog at the 5′ prime terminus. 5′-phosphate modificationsof the antisense strand include those which are compatible withRISC-mediated gene silencing. Suitable modifications include:5′-monophosphate ((HO)2(O)P—O-5′); 5′-diphosphate((HO)2(O)P—O—P(HO)(O)—O-5′); 5′-triphosphate((HO)2(O)P—O—(HO)(O)P—O—P(HO)(O)—O-5′); 5′-guanosine cap (7-methylatedor non-methylated) (7m-G-O-5′-(HO)(O)P—O—(HO)(O)P—O—P(HO)(O)—O-5′);5′-adenosine cap (Appp), and any modified or unmodified nucleotide capstructure (N—O-5′-(HO)(O)P—O—(HO)(O)P—O—P(HO)(O)—O-5′);5′-monothiophosphate (phosphorothioate; (HO)2(S)P—O-5′);5′-monodithiophosphate (phosphorodithioate; (HO)(HS)(S)P—O-5′),5′-phosphorothiolate ((HO)2(O)P—S-5′); any additional combination ofoxygen/sulfur replaced monophosphate, diphosphate and triphosphates(e.g. 5′-alpha-thiotriphosphate, 5′-gamma-thiotriphosphate, etc.),5′-phosphoramidates ((HO)2(O)P—NH-5′, (HO)(NH2)(O)P—O-5′),5′-alkylphosphonates (R=alkyl=methyl, ethyl, isopropyl, propyl, etc.,e.g. RP(OH)(O)—O-5′-, (OH)2(O)P-5′-CH2—), 5′-alkyletherphosphonates(R=alkylether=methoxymethyl (MeOCH2—), ethoxymethyl, etc., e.g.RP(OH)(O)—O-5′-).

The sense strand can be modified in order to inactivate the sense strandand prevent formation of an active RISC, thereby potentially reducingoff-target effects. This can be accomplished by a modification whichprevents 5′-phosphorylation of the sense strand, e.g., by modificationwith a 5′-O-methyl ribonucleotide (see Nykänen et al., (2001) ATPrequirements and small interfering RNA structure in the RNA interferencepathway. Cell 107, 309-321.) Other modifications which preventphosphorylation can also be used, e.g., simply substituting the 5′-OH byH rather than O-Me. Alternatively, a large bulky group may be added tothe 5′-phosphate turning it into a phosphodiester linkage.

Non-Natural Nucleobases

Nitropyrrolyl and nitroindolyl are non-natural nucleobases that aremembers of a class of compounds known as universal bases. Universalbases are those compounds that can replace any of the four naturallyoccurring bases without substantially affecting the melting behavior oractivity of the oligonucleotide duplex. In contrast to the stabilizing,hydrogen-bonding interactions associated with naturally occurringnucleobases, it is postulated that oligonucleotide duplexes containing3-nitropyrrolyl nucleobases are stabilized solely by stackinginteractions. The absence of significant hydrogen-bonding interactionswith nitropyrrolyl nucleobases obviates the specificity for a specificcomplementary base. In addition, various reports confirm that 4-, 5- and6-nitroindolyl display very little specificity for the four naturalbases. Interestingly, an oligonucleotide duplex containing5-nitroindolyl was more stable than the corresponding oligonucleotidescontaining 4-nitroindolyl and 6-nitroindolyl. Procedures for thepreparation of 1-(2′-O-methyl-β-D-ribofuranosyl)-5-nitroindole aredescribed in Gaubert, G.; Wengel, J. Tetrahedron Letters 2004, 45, 5629.Other universal bases amenable to the present invention includehypoxanthinyl, isoinosinyl, 2-aza-inosinyl, 7-deaza-inosinyl,nitroimidazolyl, nitropyrazolyl, nitrobenzimidazolyl, nitroindazolyl,aminoindolyl, pyrrolopyrimidinyl, and structural derivatives thereof.For a more detailed discussion, including synthetic procedures, ofnitropyrrolyl, nitroindolyl, and other universal bases mentioned abovesee Vallone et al., Nucleic Acids Research, 27(17):3589-3596 (1999);Loakes et al., J. Mol. Bio., 270:426-436 (1997); Loakes et al., NucleicAcids Research, 22(20):4039-4043 (1994); Oliver et al., Organic Letters,Vol. 3(13):1977-1980 (2001); Amosova et al., Nucleic Acids Research,25(10):1930-1934 (1997); Loakes et al., Nucleic Acids Research,29(12):2437-247 (2001); Bergstrom et al., J. Am. Chem. Soc.,117:1201-1209 (1995); Franchetti et al., Biorg. Med. Chem. Lett.11:67-69 (2001); and Nair et al., Nucelosides, Nucleotides & NucleicAcids, 20(4-7):735-738 (2001).

Difluorotolyl is a non-natural nucleobase that functions as a universalbase. Difluorotolyl is an isostere of the natural nucleobase thymine.But unlike thymine, difluorotolyl shows no appreciable selectivity forany of the natural bases. Other aromatic compounds that function asuniversal bases and are amenable to the present invention are4-fluoro-6-methylbenzimidazole and 4-methylbenzimidazole. In addition,the relatively hydrophobic isocarbostyrilyl derivatives 3-methylisocarbostyrilyl, 5-methyl isocarbostyrilyl, and 3-methyl-7-propynylisocarbostyrilyl are universal bases which cause only slightdestabilization of oligonucleotide duplexes compared to theoligonucleotide sequence containing only natural bases. Othernon-natural nucleobases contemplated in the present invention include7-azaindolyl, 6-methyl-7-azaindolyl, imidizopyridinyl,9-methyl-imidizopyridinyl, pyrrolopyrizinyl, isocarbostyrilyl,7-propynyl isocarbostyrilyl, propynyl-7-azaindolyl,2,4,5-trimethylphenyl, 4-methylindolyl, 4,6-dimethylindolyl, phenyl,napthalenyl, anthracenyl, phenanthracenyl, pyrenyl, stilbenzyl,tetracenyl, pentacenyl, and structural derivates thereof. For a moredetailed discussion, including synthetic procedures, of difluorotolyl,4-fluoro-6-methylbenzimidazole, 4-methylbenzimidazole, and othernon-natural bases mentioned above, see: Schweitzer et al., J. Org.Chem., 59:7238-7242 (1994); Berger et al., Nucleic Acids Research,28(15):2911-2914 (2000); Moran et al., J. Am. Chem. Soc., 119:2056-2057(1997); Morales et al., J. Am. Chem. Soc., 121:2323-2324 (1999); Guckianet al., J. Am. Chem. Soc., 118:8182-8183 (1996); Morales et al., J. Am.Chem. Soc., 122(6):1001-1007 (2000); McMinn et al., J. Am. Chem. Soc.,121:11585-11586 (1999); Guckian et al., J. Org. Chem., 63:9652-9656(1998); Moran et al., Proc. Natl. Acad. Sci., 94:10506-10511 (1997); Daset al., J. Chem. Soc., Perkin Trans., 1:197-206 (2002); Shibata et al.,J. Chem. Soc., Perkin Trans., 1:1605-1611 (2001); Wu et al., J. Am.Chem. Soc., 122(32):7621-7632 (2000); O'Neill et al., J. Org. Chem.,67:5869-5875 (2002); Chaudhuri et al., J. Am. Chem. Soc.,117:10434-10442 (1995); and U.S. Pat. No. 6,218,108.

Transport of iRNA Agents into Cells

Not wishing to be bound by any theory, the chemical similarity betweencholesterol-conjugated iRNA agents and certain constituents oflipoproteins (e.g. cholesterol, cholesteryl esters, phospholipids) maylead to the association of iRNA agents with lipoproteins (e.g. LDL, HDL)in blood and or the interaction of the iRNA agent with cellularcomponents having an affinity for cholesterol, e.g. components of thecholesterol transport pathway. Lipoproteins as well as theirconstituents are taken up and processed by cells by various active andpassive transport mechanisms, for example, without limitation,endocytosis of LDL-receptor bound LDL, endocytosis of oxidized orotherwise modified LDLs through interaction with Scavenger receptor A,Scavenger receptor B1-mediated uptake of HDL cholesterol in the liver,pinocytosis, or transport of cholesterol across membranes by ABC(ATP-binding cassette) transporter proteins, e.g. ABC-A1, ABC-G1 orABC-G4. Hence, cholesterol-conjugated iRNA agents could enjoyfacilitated uptake by cells possessing such transport mechanisms, e.g.cells of the liver. As such, the present invention provides evidence andgeneral methods for targeting iRNA agents to cells expressing certaincell surface components, e.g. receptors, by conjugating a natural ligandfor such component (e.g. cholesterol) to the iRNA agent, or byconjugating a chemical moiety (e.g. cholesterol) to the iRNA agent whichassociates with or binds to a natural ligand for the component (e.g.LDL, HDL).

Other Embodiments

An iRNA agent, can be produced in a cell in viva, e.g., from exogenousDNA templates that are delivered into the cell. For example, the DNAtemplates can be inserted into vectors and used as gene therapy vectors.Gene therapy vectors can be delivered to a subject by, for example,intravenous injection, local administration (U.S. Pat. No. 5,328,470),or by stereotactic injection (see, e.g., Chen et al. Proc. Natl. Acad.Sci. USA 91:3054-3057, 1994). The pharmaceutical preparation of the genetherapy vector can include the gene therapy vector in an acceptablediluent, or can comprise a slow release matrix in which the genedelivery vehicle is imbedded. The DNA templates, for example, caninclude two transcription units, one that produces a transcript thatincludes the top strand of an iRNA agent and one that produces atranscript that includes the bottom strand of an iRNA agent. When thetemplates are transcribed, the iRNA agent is produced, and processedinto siRNA agent fragments that mediate gene silencing.

Formulation

The present invention also includes pharmaceutical compositions andformulations which include the dsRNA compounds of the invention. Thepharmaceutical compositions of the present invention may be administeredin a number of ways depending upon whether local or systemic treatmentis desired and upon the area to be treated. Administration may betopical, pulmonary, e.g., by inhalation or insufflation of powders oraerosols, including by nebulizer; intratracheal, intranasal, epidermaland transdermal, oral or parenteral. Parenteral administration includesintravenous, intraarterial, subcutaneous, intraperitoneal orintramuscular injection or infusion; or intracranial, e.g., intrathecalor intraventricular, administration.

Pharmaceutical compositions and formulations for topical administrationmay include transdermal patches, ointments, lotions, creams, gels,drops, suppositories, sprays, liquids and powders. Conventionalpharmaceutical carriers, aqueous, powder or oily bases, thickeners andthe like may be necessary or desirable. Coated condoms, gloves and thelike may also be useful. Preferred topical formulations include those inwhich the dsRNAs of the invention are in admixture with a topicaldelivery agent such as lipids, liposomes, fatty acids, fatty acidesters, steroids, chelating agents and surfactants. Preferred lipids andliposomes include neutral (e.g. dioleoylphosphatidyl ethanolamine=DOPE,dimyristoylphosphatidyl choline=DMPC, distearolyphosphatidyl choline)negative (e.g. dimyristoylphosphatidyl glycerol=DMPG) and cationic (e.g.dioleoyltetramethyl-aminopropyl=DOTAP and dioleoylphosphatidylethanolamine=DOTMA), e.g.(+/−)-N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(dodecyloxy)-1-propanaminiumbromide=GAP-DLRIE). DsRNAs of the invention may be encapsulated withinliposomes or may form complexes thereto, in particular to cationicliposomes. Alternatively, dsRNAs may be complexed to lipids, inparticular to cationic lipids. Preferred fatty acids and esters includebut are not limited arachidonic acid, oleic acid, eicosanoic acid,lauric acid, caprylic acid, capric acid, myristic acid, palmitic acid,stearic acid, linoleic acid, linolenic acid, dicaprate, tricaprate,monoolein, dilaurin, glyceryl 1-monocaprate,1-dodecylazacycloheptan-2-one, an acylcamitine, an acylcholine, or aC₁₋₁₀ alkyl ester (e.g. isopropylmyristate IPM), monoglyceride,diglyceride or pharmaceutically acceptable salt thereof. Topicalformulations are described in detail in U.S. patent application Ser. No.09/315,298 filed on May 20, 1999 which is incorporated herein byreference in its entirety.

Compositions and formulations for oral administration include powders orgranules, microparticulates, nanoparticulates, suspensions or solutionsin water or non-aqueous media, capsules, gel capsules, sachets, tabletsor minitablets. Thickeners, flavoring agents, diluents, emulsifiers,dispersing aids or binders may be desirable. Preferred oral formulationsare those in which dsRNAs of the invention are administered inconjunction with one or more penetration enhancers, surfactants, andchelators. Preferred surfactants include fatty acids and or esters orsalts thereof, bile acids and/or salts thereof. Preferred bileacids/salts include chenodeoxycholic acid (CDCA) andursodeoxychenodeoxycholic acid (UDCA), cholic acid, dehydrocholic acid,deoxycholic acid, glucholic acid, glycholic acid, glycodeoxycholic acid,taurocholic acid, taurodeoxycholic acid, sodiumtauro-24,25-dihydro-fusidate and sodium glycodihydrofusidate. Preferredfatty acids include arachidonic acid, undecanoic acid, oleic acid,lauric acid, caprylic acid, capric acid, myristic acid, palmitic acid,stearic acid, linoleic acid, linolenic acid, dicaprate, tricaprate,monoolein, dilaurin, glyceryl 1-monocaprate,1-dodecylazacycloheptan-2-one, an acylcamitine, an acylcholine, or amonoglyceride, a diglyceride or a pharmaceutically acceptable saltthereof (e.g. sodium). Also preferred are combinations of penetrationenhancers, for example, fatty acids/salts in combination with bileacids/salts. A particularly preferred combination is the sodium salt oflauric acid, capric acid and UDCA. Further penetration enhancers includepolyoxyethylene-9-lauryl ether, polyoxyethylene-20-cetyl ether. DsRNAsof the invention may be delivered orally, in granular form includingsprayed dried particles, or complexed to form micro or nanoparticles.DsRNA complexing agents include poly-amino acids; polyimines;polyacrylates; polyalkylacrylates, polyoxethanes,polyalkylcyanoacrylates; cationized gelatins, albumins, starches,acrylates, polyethyleneglycols (PEG) and starches;polyalkylcyanoacrylates; DEAE-derivatized polyimines, pollulans,celluloses and starches. Particularly preferred complexing agentsinclude chitosan, N-trimethylchitosan, poly-L-lysine, polyhistidine,polyornithine, polyspermines, protamine, polyvinylpyridine,polythiodiethylaminomethylethylene P(TDAE), polyaminostyrene (e.g.p-amino), poly(methylcyanoacrylate), poly(ethylcyanoacrylate),poly(butylcyanoacrylate), poly(isobutyl cyanoacrylate),poly(isohexylcynaoacrylate), DEAE-methacrylate, DEAE-hexylacrylate,DEAE-acrylamide, DEAE-albumin and DEAE-dextran, polymethylacrylate,polyhexylacrylate, poly(D,L-lactic acid), poly(DL-lactic-co-glycolicacid (PLGA), alginate, and polyethyleneglycol (PEG). Oral formulationsfor dsRNAs and their preparation are described in detail in U.S.application. Ser. No. 08/886,829 (filed Jul. 1, 1997), Ser. No.09/108,673 (filed Jul. 1, 1998), Ser. No. 09/256,515 (filed Feb. 23,1999), Ser. No. 09/082,624 (filed May 21, 1998) and Ser. No. 09/315,298(filed May 20, 1999), each of which is incorporated herein by referencein their entirety.

Compositions and formulations for parenteral, intrathecal orintraventricular administration may include sterile aqueous solutionswhich may also contain buffers, diluents and other suitable additivessuch as, but not limited to, penetration enhancers, carrier compoundsand other pharmaceutically acceptable carriers or excipients.

Pharmaceutical compositions of the present invention include, but arenot limited to, solutions, emulsions, and liposome-containingformulations. These compositions may be generated from a variety ofcomponents that include, but are not limited to, preformed liquids,self-emulsifying solids and self-emulsifying semisolids.

The pharmaceutical formulations of the present invention, which mayconveniently be presented in unit dosage form, may be prepared accordingto conventional techniques well known in the pharmaceutical industry.Such techniques include the step of bringing into association the activeingredients with the pharmaceutical carrier(s) or excipient(s). Ingeneral, the formulations are prepared by uniformly and intimatelybringing into association the active ingredients with liquid carriers orfinely divided solid carriers or both, and then, if necessary, shapingthe product.

The compositions of the present invention may be formulated into any ofmany possible dosage forms such as, but not limited to, tablets,capsules, gel capsules, liquid syrups, soft gels, suppositories, andenemas. The compositions of the present invention may also be formulatedas suspensions in aqueous, non-aqueous or mixed media. Aqueoussuspensions may further contain substances which increase the viscosityof the suspension including, for example, sodium carboxymethylcellulose,sorbitol and/or dextran. The suspension may also contain stabilizers.

In one embodiment of the present invention the pharmaceuticalcompositions may be formulated and used as foams. Pharmaceutical foamsinclude formulations such as, but not limited to, emulsions,microemulsions, creams, jellies and liposomes. While basically similarin nature these formulations vary in the components and the consistencyof the final product. The preparation of such compositions andformulations is generally known to those skilled in the pharmaceuticaland formulation arts and may be applied to the formulation of thecompositions of the present invention.

Emulsions

The compositions of the present invention may be prepared and formulatedas emulsions. Emulsions are typically heterogenous systems of one liquiddispersed in another in the form of droplets usually exceeding 0.1 μm indiameter (Idson, in Pharmaceutical Dosage Forms, Lieberman, Rieger andBanker (Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., volume 1, p.199; Rosoff, in Pharmaceutical Dosage Forms, Lieberman, Rieger andBanker (Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., Volume 1, p.245; Block in Pharmaceutical Dosage Forms, Lieberman, Rieger and Banker(Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., volume 2, p. 335;Higuchi et al., in Remington's Pharmaceutical Sciences, Mack PublishingCo., Easton, Pa., 1985, p. 301). Emulsions are often biphasic systemscomprising two immiscible liquid phases intimately mixed and dispersedwith each other. In general, emulsions may be of either the water-in-oil(w/o) or the oil-in-water (o/w) variety. When an aqueous phase is finelydivided into and dispersed as minute droplets into a bulk oily phase,the resulting composition is called a water-in-oil (w/o) emulsion.Alternatively, when an oily phase is finely divided into and dispersedas minute droplets into a bulk aqueous phase, the resulting compositionis called an oil-in-water (o/w) emulsion. Emulsions may containadditional components in addition to the dispersed phases, and theactive drug which may be present as a solution in either the aqueousphase, oily phase or itself as a separate phase. Pharmaceuticalexcipients such as emulsifiers, stabilizers, dyes, and anti-oxidants mayalso be present in emulsions as needed. Pharmaceutical emulsions mayalso be multiple emulsions that are comprised of more than two phasessuch as, for example, in the case of oil-in-water-in-oil (o/w/o) andwater-in-oil-in-water (w/o/w) emulsions. Such complex formulations oftenprovide certain advantages that simple binary emulsions do not. Multipleemulsions in which individual oil droplets of an o/w emulsion enclosesmall water droplets constitute a w/o/w emulsion. Likewise a system ofoil droplets enclosed in globules of water stabilized in an oilycontinuous phase provides an o/w/o emulsion.

Emulsions are characterized by little or no thermodynamic stability.Often, the dispersed or discontinuous phase of the emulsion is welldispersed into the external or continuous phase and maintained in thisform through the means of emulsifiers or the viscosity of theformulation. Either of the phases of the emulsion may be a semisolid ora solid, as is the case of emulsion-style ointment bases and creams.Other means of stabilizing emulsions entail the use of emulsifiers thatmay be incorporated into either phase of the emulsion. Emulsifiers maybroadly be classified into four categories: synthetic surfactants,naturally occurring emulsifiers, absorption bases, and finely dispersedsolids (Idson, in Pharmaceutical Dosage Forms, Lieberman, Rieger andBanker (Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., volume 1, p.199).

Synthetic surfactants, also known as surface active agents, have foundwide applicability in the formulation of emulsions and have beenreviewed in the literature (Rieger, in Pharmaceutical Dosage Forms,Lieberman, Rieger and Banker (Eds.), 1988, Marcel Dekker, Inc., NewYork, N.Y., volume 1, p. 285; Idson, in Pharmaceutical Dosage Forms,Lieberman, Rieger and Banker (Eds.), Marcel Dekker, Inc., New York,N.Y., 1988, volume 1, p. 199). Surfactants are typically amphiphilic andcomprise a hydrophilic and a hydrophobic portion. The ratio of thehydrophilic to the hydrophobic nature of the surfactant has been termedthe hydrophile/lipophile balance (HLB) and is a valuable tool incategorizing and selecting surfactants in the preparation offormulations. Surfactants may be classified into different classes basedon the nature of the hydrophilic group: nonionic, anionic, cationic andamphoteric (Rieger, in Pharmaceutical Dosage Forms, Lieberman, Riegerand Banker (Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., volume 1,p. 285).

Naturally occurring emulsifiers used in emulsion formulations includelanolin, beeswax, phosphatides, lecithin and acacia. Absorption basespossess hydrophilic properties such that they can soak up water to formw/o emulsions yet retain their semisolid consistencies, such asanhydrous lanolin and hydrophilic petrolatum. Finely divided solids havealso been used as good emulsifiers especially in combination withsurfactants and in viscous preparations. These include polar inorganicsolids, such as heavy metal hydroxides, nonswelling clays such asbentonite, attapulgite, hectorite, kaolin, montmorillonite, colloidalaluminum silicate and colloidal magnesium aluminum silicate, pigmentsand nonpolar solids such as carbon or glyceryl tristearate.

A large variety of non-emulsifying materials are also included inemulsion formulations and contribute to the properties of emulsions.These include fats, oils, waxes, fatty acids, fatty alcohols, fattyesters, humectants, hydrophilic colloids, preservatives and antioxidants(Block, in Pharmaceutical Dosage Forms, Lieberman, Rieger and Banker(Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., volume 1, p. 335;Idson, in Pharmaceutical Dosage Forms, Lieberman, Rieger and Banker(Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., vol. 1, p. 199).

Hydrophilic colloids or hydrocolloids include naturally occurring gumsand synthetic polymers such as polysaccharides (for example, acacia,agar, alginic acid, carrageenan, guar gum, karaya gum, and tragacanth),cellulose derivatives (for example, carboxymethylcellulose andcarboxypropylcellulose), and synthetic polymers (for example, carbomers,cellulose ethers, and carboxyvinyl polymers). These disperse or swell inwater to form colloidal solutions that stabilize emulsions by formingstrong interfacial films around the dispersed-phase droplets and byincreasing the viscosity of the external phase.

Since emulsions often contain a number of ingredients such ascarbohydrates, proteins, sterols and phosphatides that may readilysupport the growth of microbes, these formulations often incorporatepreservatives. Commonly used preservatives included in emulsionformulations include methyl paraben, propyl paraben, quaternary ammoniumsalts, benzalkonium chloride, esters of p-hydroxybenzoic acid, and boricacid. Antioxidants are also commonly added to emulsion formulations toprevent deterioration of the formulation. Antioxidants used may be freeradical scavengers such as tocopherols, alkyl gallates, butylatedhydroxyanisole, butylated hydroxytoluene, or reducing agents such asascorbic acid and sodium metabisulfite, and antioxidant synergists suchas citric acid, tartaric acid, and lecithin.

The application of emulsion formulations via dermatological, oral andparenteral routes and methods for their manufacture have been reviewedin the literature (Idson, in Pharmaceutical Dosage Forms, Lieberman,Rieger and Banker (Eds.), 1988, Marcel Dekker, Inc., New York, N.Y.,volume 1, p. 199). Emulsion formulations for oral delivery have beenvery widely used because of ease of formulation, as well as efficacyfrom an absorption and bioavailability standpoint (Rosoff, inPharmaceutical Dosage Forms, Lieberman, Rieger and Banker (Eds.), 1988,Marcel Dekker, Jnc., New York, N.Y., volume 1, p. 245; Idson, inPharmaceutical Dosage Forms, Lieberman, Rieger and Banker (Eds.), 1988,Marcel Dekker, Inc., New York, N.Y., volume 1, p. 199). Mineral-oil baselaxatives, oil-soluble vitamins and high fat nutritive preparations areamong the materials that have commonly been administered orally as o/wemulsions.

In one embodiment of the present invention, the compositions of dsRNAsand nucleic acids are formulated as microemulsions. A microemulsion maybe defined as a system of water, oil and amphiphile which is a singleoptically isotropic and thermodynamically stable liquid solution(Rosoff, in Pharmaceutical Dosage Forms, Lieberman, Rieger and Banker(Eds.), 1988, Marcel Dekker, Inc., New York, N.Y., volume 1, p. 245).Typically microemulsions are systems that are prepared by firstdispersing an oil in an aqueous surfactant solution and then adding asufficient amount of a fourth component, generally an intermediatechain-length alcohol to form a transparent system. Therefore,microemulsions have also been described as thermodynamically stable,isotropically clear dispersions of two immiscible liquids that arestabilized by interfacial films of surface-active molecules (Leung andShah, in: Controlled Release of Drugs: Polymers and Aggregate Systems,Rosoff, M., Ed., 1989, VCH Publishers, New York, pages 185-215).Microemulsions commonly are prepared via a combination of three to fivecomponents that include oil, water, surfactant, cosurfactant andelectrolyte. Whether the microemulsion is of the water-in-oil (w/o) oran oil-in-water (o/w) type is dependent on the properties of the oil andsurfactant used and on the structure and geometric packing of the polarheads and hydrocarbon tails of the surfactant molecules (Schott, inRemington's Pharmaceutical Sciences, Mack Publishing Co., Easton, Pa.,1985, p. 271).

The phenomenological approach utilizing phase diagrams has beenextensively studied and has yielded a comprehensive knowledge, to oneskilled in the art, of how to formulate microemulsions (Rosoff, inPharmaceutical Dosage Forms, Lieberman, Rieger and Banker (Eds.), 1988,Marcel Dekker, Inc., New York, N.Y., volume 1, p. 245; Block, inPharmaceutical Dosage Forms, Lieberman, Rieger and Banker (Eds.), 1988,Marcel Dekker, Inc., New York, N.Y., volume 1, p. 335). Compared toconventional emulsions, microemulsions offer the advantage ofsolubilizing water-insoluble drugs in a formulation of thermodynamicallystable droplets that are formed spontaneously.

Surfactants used in the preparation of microemulsions include, but arenot limited to, ionic surfactants, non-ionic surfactants, Brij 96,polyoxyethylene oleyl ethers, polyglycerol fatty acid esters,tetraglycerol monolaurate (ML310), tetraglycerol monooleate (MO310),hexaglycerol monooleate (PO310), hexaglycerol pentaoleate (PO500),decaglycerol monocaprate (MCA750), decaglycerol monooleate (MO750),decaglycerol sequioleate (SO750), decaglycerol decaoleate (DAO750),alone or in combination with cosurfactants. The cosurfactant, usually ashort-chain alcohol such as ethanol, 1-propanol, and 1-butanol, servesto increase the interfacial fluidity by penetrating into the surfactantfilm and consequently creating a disordered film because of the voidspace generated among surfactant molecules. Microemulsions may, however,be prepared without the use of cosurfactants and alcohol-freeself-emulsifying microemulsion systems are known in the art. The aqueousphase may typically be, but is not limited to, water, an aqueoussolution of the drug, glycerol, PEG300, PEG400, polyglycerols, propyleneglycols, and derivatives of ethylene glycol. The oil phase may include,but is not limited to, materials such as Captex 300, Captex 355, CapmulMCM, fatty acid esters, medium chain (C₈-C₁₂) mono, di, andtri-glycerides, polyoxyethylated glyceryl fatty acid esters, fattyalcohols, polyglycolized glycerides, saturated polyglycolized C₈-C₁₀glycerides, vegetable oils and silicone oil.

Microemulsions are particularly of interest from the standpoint of drugsolubilization and the enhanced absorption of drugs. Lipid basedmicroemulsions (both o/w and w/o) have been proposed to enhance the oralbioavailability of drugs, including peptides (Constantinides et al.,Pharmaceutical Research, 1994, 11, 1385-1390; Ritschel, Meth. Find. Exp.Clin. Pharmacol., 1993, 13, 205). Microemulsions afford advantages ofimproved drug solubilization, protection of drug from enzymatichydrolysis, possible enhancement of drug absorption due tosurfactant-induced alterations in membrane fluidity and permeability,ease of preparation, ease of oral administration over solid dosageforms, improved clinical potency, and decreased toxicity (Constantinideset al., Pharmaceutical Research, 1994, 11, 1385; Ho et al., J. Pharm.Sci., 1996, 85, 138-143). Often microemulsions may form spontaneouslywhen their components are brought together at ambient temperature. Thismay be particularly advantageous when formulating thermolabile drugs,peptides or dsRNAs. Microemulsions have also been effective in thetransdermal delivery of active components in both cosmetic andpharmaceutical applications. It is expected that the microemulsioncompositions and formulations of the present invention will facilitatethe increased systemic absorption of dsRNAs and nucleic acids from thegastrointestinal tract, as well as improve the local cellular uptake ofdsRNAs and nucleic acids within the gastrointestinal tract, vagina,buccal cavity and other areas of administration.

Microemulsions of the present invention may also contain additionalcomponents and additives such as sorbitan monostearate (Grill 3),Labrasol, and penetration enhancers to improve the properties of theformulation and to enhance the absorption of the dsRNAs and nucleicacids of the present invention. Penetration enhancers used in themicroemulsions of the present invention may be classified as belongingto one of five broad categories surfactants, fatty acids, bile salts,chelating agents, and non-chelating non-surfactants (Lee et al.,Critical Reviews in Therapeutic Drug Carrier Systems, 1991, p. 92). Eachof these classes has been discussed above.

Liposomes

There are many organized surfactant structures besides microemulsionsthat have been studied and used for the formulation of drugs. Theseinclude monolayers, micelles, bilayers and vesicles. Vesicles, such asliposomes, have attracted great interest because of their specificityand the duration of action they offer from the standpoint of drugdelivery. As used in the present invention, the term “liposome” means avesicle composed of amphiphilic lipids arranged in a spherical bilayeror bilayers.

Liposomes are unilamellar or multilamellar vesicles which have amembrane formed from a lipophilic material and an aqueous interior. Theaqueous portion contains the composition to be delivered. Cationicliposomes possess the advantage of being able to fuse to the cell wall.Non-cationic liposomes, although not able to fuse as efficiently withthe cell membrane, are taken up by macrophages in vivo.

In order to cross intact mammalian skin, lipid vesicles must passthrough a series of fine pores, each with a diameter less than 50 nm,under the influence of a suitable transdermal gradient. Therefore, it isdesirable to use a liposome which is highly deformable and able to passthrough such fine pores.

Further advantages of liposomes include; liposomes obtained from naturalphospholipids are biocompatible and biodegradable; liposomes canincorporate a wide range of water and lipid soluble drugs; liposomes canprotect encapsulated drugs in their internal compartments frommetabolism and degradation (Rosoff, in Pharmaceutical Dosage Forms,Lieberman, Rieger and Banker (Eds.), 1988, Marcel Dekker, Inc., NewYork, N.Y., volume 1, p. 245). Important considerations in thepreparation of liposome formulations are the lipid surface charge,vesicle size and the aqueous volume of the liposomes.

Liposomes are useful for the transfer and delivery of active ingredientsto the site of action. Because the liposomal membrane is structurallysimilar to biological membranes, when liposomes are applied to a tissue,the liposomes start to merge with the cellular membranes and as themerging of the liposome and cell progresses, the liposomal contents areemptied into the cell where the active agent may act.

Liposomal formulations have been the focus of extensive investigation asthe mode of delivery for many drugs. There is growing evidence that fortopical administration, liposomes present several advantages over otherformulations. Such advantages include reduced side-effects related tohigh systemic absorption of the administered drug, increasedaccumulation of the administered drug at the desired target, and theability to administer a wide variety of drugs, both hydrophilic andhydrophobic, into the skin.

Several reports have detailed the ability of liposomes to deliver agentsincluding high-molecular weight DNA into the skin. Compounds includinganalgesics, antibodies, hormones and high-molecular weight DNAs havebeen administered to the skin. The majority of applications resulted inthe targeting of the upper epidermis

Liposomes fall into two broad classes. Cationic liposomes are positivelycharged liposomes which interact with the negatively charged DNAmolecules to form a stable complex. The positively charged DNA/liposomecomplex binds to the negatively charged cell surface and is internalizedin an endosome. Due to the acidic pH within the endosome, the liposomesare ruptured, releasing their contents into the cell cytoplasm (Wang etal., Biochem. Biophys. Res. Commun., 1987, 147, 980-985).

Liposomes which are pH-sensitive or negatively-charged, entrap DNArather than complex with it. Since both the DNA and the lipid aresimilarly charged, repulsion rather than complex formation occurs.Nevertheless, some DNA is entrapped within the aqueous interior of theseliposomes. pH-sensitive liposomes have been used to deliver DNA encodingthe thymidine kinase gene to cell monolayers in culture. Expression ofthe exogenous gene was detected in the target cells (Zhou et al.,Journal of Controlled Release, 1992, 19, 269-274).

One major type of liposomal composition includes phospholipids otherthan naturally derived phosphatidylcholine. Neutral liposomecompositions, for example, can be formed from dimyristoylphosphatidylcholine (DMPC) or dipalmitoyl phosphatidylcholine (DPPC).Anionic liposome compositions generally are formed from dimyristoylphosphatidylglycerol, while anionic fusogenic liposomes are formedprimarily from dioleoyl phosphatidylethanolamine (DOPE). Another type ofliposomal composition is formed from phosphatidylcholine (PC) such as,for example, soybean PC, and egg PC. Another type is formed frommixtures of phospholipid and/or phosphatidylcholine and or cholesterol.

Several studies have assessed the topical delivery of liposomal drugformulations to the skin. Application of liposomes containing interferonto guinea pig skin resulted in a reduction of skin herpes sores whiledelivery of interferon via other means (e.g. as a solution or as anemulsion) were ineffective (Weiner et al., Journal of Drug Targeting,1992, 2, 405-410). Further, an additional study tested the efficacy ofinterferon administered as part of a liposomal formulation to theadministration of interferon using an aqueous system, and concluded thatthe liposomal formulation was superior to aqueous administration (duPlessis et al., Antiviral Research, 1992, 18, 259-265).

Non-ionic liposomal systems have also been examined to determine theirutility in the delivery of drugs to the skin, in particular systemscomprising non-ionic surfactant and cholesterol. Non-ionic liposomalformulations comprising Novasome.™. I (glyceryldilaurate/cholesterol/polyoxyethylene-10-stearyl ether) and Novasome.™.II (glyceryl distearate/cholesterol/polyoxyethylene-10-stearyl ether)were used to deliver cyclosporin-A into the dermis of mouse skin.Results indicated that such non-ionic liposomal systems were effectivein facilitating the deposition of cyclosporin-A into different layers ofthe skin (Hu et al. S. T. P. Pharma. Sci., 1994, 4, 6, 466).

Liposomes also include “sterically stabilized” liposomes, a term which,as used herein, refers to liposomes comprising one or more specializedlipids that, when incorporated into liposomes, result in enhancedcirculation lifetimes relative to liposomes lacking such specializedlipids. Examples of sterically stabilized liposomes are those in whichpart of the vesicle-forming lipid portion of the liposome (A) comprisesone or more glycolipids, such as monosialoganglioside G_(m)1, or (B) isderivatized with one or more hydrophilic polymers, such as apolyethylene glycol (PEG) moiety. While not wishing to be bound by anyparticular theory, it is thought in the art that, at least forsterically stabilized liposomes containing gangliosides, sphingomyelin,or PEG-derivatized lipids, the enhanced circulation half-life of thesesterically stabilized liposomes derives from a reduced uptake into cellsof the reticuloendothelial system (RES) (Allen et al., FEBS Letters,1987, 223, 42; Wu et al., Cancer Research, 1993, 53, 3765).

Various liposomes comprising one or more glycolipids are known in theart. Papahadjopoulos et al. (Ann. N.Y. Acad. Sci., 1987, 507, 64)reported the ability of monosialoganglioside G_(m)1, galactocerebrosidesulfate and phosphatidylinositol to improve blood half-lives ofliposomes. These findings were expounded upon by Gabizon et al. (Proc.Natl. Acad. Sci. U.S.A., 1988, 85, 6949). U.S. Pat. No. 4,837,028 and WO88/04924, both to Allen et al., disclose liposomes comprising (1)sphingomyelin and (2) the ganglioside G_(m)1 or a galactocerebrosidesulfate ester. U.S. Pat. No. 5,543,152 (Webb et al.) discloses liposomescomprising sphingomyelin. Liposomes comprising1,2-sn-dimyristoylphosphat-idylcholine are disclosed in WO 97/13499 (Limet al).

Many liposomes comprising lipids derivatized with one or morehydrophilic polymers, and methods of preparation thereof, are known inthe art. Sunamoto et al. (Bull. Chem. Soc. Jpn., 1980, 53, 2778)described liposomes comprising a nonionic detergent, 2C_(1215G), thatcontains a PEG moiety. Illum et al. (FEBS Lett., 1984, 167, 79) notedthat hydrophilic coating of polystyrene particles with polymeric glycolsresults in significantly enhanced blood half-lives. Syntheticphospholipids modified by the attachment of carboxylic groups ofpolyalkylene glycols (e.g., PEG) are described by Sears (U.S. Pat. Nos.4,426,330 and 4,534,899). Klibanov et al. (FEBS Lett., 1990, 268, 235)described experiments demonstrating that liposomes comprisingphosphatidylethanolamine (PE) derivatized with PEG or PEG stearate havesignificant increases in blood circulation half-lives. Blume et al.(Biochimica et Biophysica Acta, 1990, 1029, 91) extended suchobservations to other PEG-derivatized phospholipids, e.g., DSPE-PEG,formed from the combination of distearoylphosphatidylethanolamine (DSPE)and PEG. Liposomes having covalently bound PEG moieties on theirexternal surface are described in European Patent No. EP 0 45 131 B1 andWO 90/04384 to Fisher. Liposome compositions containing 1-20 molepercent of PE derivatized with PEG, and methods of use thereof, aredescribed by Woodle et al. (U.S. Pat. Nos. 5,013,556 and 5,356,633) andMartin et al. (U.S. Pat. No. 5,213,804 and European Patent No. EP 0 496813 B1). Liposomes comprising a number of other lipid-polymer conjugatesare disclosed in WO 91/05545 and U.S. Pat. No. 5,225,212 (both to Martinet al.) and in WO 94/20073 (Zalipsky et al.) Liposomes comprisingPEG-modified ceramide lipids are described in WO 96/10391 (Choi et al).U.S. Pat. No. 5,540,935 (Miyazaki et al.) and U.S. Pat. No. 5,556,948(Tagawa et al.) describe PEG-containing liposomes that can be furtherderivatized with functional moieties on their surfaces.

A limited number of liposomes comprising nucleic acids are known in theart. WO 96/40062 to Thierry et al. discloses methods for encapsulatinghigh molecular weight nucleic acids in liposomes. U.S. Pat. No.5,264,221 to Tagawa et al. discloses protein-bonded liposomes andasserts that the contents of such liposomes may include dsRNA. U.S. Pat.No. 5,665,710 to Rahman et al. describes certain methods ofencapsulating oligodeoxynucleotides in liposomes. WO 97/04787 to Love etal. discloses liposomes comprising dsRNAs targeted to the raf gene.

Transfersomes are yet another type of liposomes, and are highlydeformable lipid aggregates which are attractive candidates for drugdelivery vehicles. Transfersomes may be described as lipid dropletswhich are so highly deformable that they are easily able to penetratethrough pores which are smaller than the droplet. Transfersomes areadaptable to the environment in which they are used, e.g. they areself-optimizing (adaptive to the shape of pores in the skin),self-repairing, frequently reach their targets without fragmenting, andoften self-loading. To make transfersomes it is possible to add surfaceedge-activators, usually surfactants, to a standard liposomalcomposition. Transfersomes have been used to deliver serum albumin tothe skin. The transfersome-mediated delivery of serum albumin has beenshown to be as effective as subcutaneous injection of a solutioncontaining serum albumin.

Surfactants find wide application in formulations such as emulsions(including microemulsions) and liposomes. The most common way ofclassifying and ranking the properties of the many different types ofsurfactants, both natural and synthetic, is by the use of the hydrophilelipophile balance (HLB). The nature of the hydrophilic group (also knownas the “head”) provides the most useful means for categorizing thedifferent surfactants used in formulations (Rieger, in PharmaceuticalDosage Forms, Marcel Dekker, Inc., New York, N.Y., 1988, p. 285).

If the surfactant molecule is not ionized, it is classified as anonionic surfactant. Nonionic surfactants find wide application inpharmaceutical and cosmetic products and are usable over a wide range ofpH values. In general their HLB values range from 2 to about 18depending on their structure. Nonionic surfactants include nonionicesters such as ethylene glycol esters, propylene glycol esters, glycerylesters, polyglyceryl esters, sorbitan esters, sucrose esters, andethoxylated esters. Nonionic alkanolamides and ethers such as fattyalcohol ethoxylates, propoxylated alcohols, and ethoxylated/propoxylatedblock polymers are also included in this class. The polyoxyethylenesurfactants are the most popular members of the nonionic surfactantclass.

If the surfactant molecule carries a negative charge when it isdissolved or dispersed in water, the surfactant is classified asanionic. Anionic surfactants include carboxylates such as soaps, acyllactylates, acyl amides of amino acids, esters of sulfuric acid such asalkyl sulfates and ethoxylated alkyl sulfates, sulfonates such as alkylbenzene sulfonates, acyl isethionates, acyl taurates andsulfosuccinates, and phosphates. The most important members of theanionic surfactant class are the alkyl sulfates and the soaps.

If the surfactant molecule carries a positive charge when it isdissolved or dispersed in water, the surfactant is classified ascationic. Cationic surfactants include quaternary ammonium salts andethoxylated amines. The quaternary ammonium salts are the most usedmembers of this class.

If the surfactant molecule has the ability to carry either a positive ornegative charge, the surfactant is classified as amphoteric. Amphotericsurfactants include acrylic acid derivatives, substituted alkylamides,N-alkylbetaines and phosphatides.

The use of surfactants in drug products, formulations and in emulsionshas been reviewed (Rieger, in Pharmaceutical Dosage Forms, MarcelDekker, Inc., New York, N.Y., 1988, p. 285).

Penetration Enhancers

In one embodiment, the present invention employs various penetrationenhancers to effect the efficient delivery of nucleic acids,particularly dsRNAs, to the skin of animals. Most drugs are present insolution in both ionized and nonionized forms. However, usually onlylipid soluble or lipophilic drugs readily cross cell membranes. It hasbeen discovered that even non-lipophilic drugs may cross cell membranesif the membrane to be crossed is treated with a penetration enhancer. Inaddition to aiding the diffusion of non-lipophilic drugs across cellmembranes, penetration enhancers also enhance the permeability oflipophilic drugs.

Penetration enhancers may be classified as belonging to one of fivebroad categories, i.e., surfactants, fatty acids, bile salts, chelatingagents, and non-chelating non-surfactants (Lee et al., Critical Reviewsin Therapeutic Drug Carrier Systems, 1991, p. 92). Each of the abovementioned classes of penetration enhancers are described below ingreater detail.

Surfactants: In connection with the present invention, surfactants (or“surface-active agents”) are chemical entities which, when dissolved inan aqueous solution, reduce the surface tension of the solution or theinterfacial tension between the aqueous solution and another liquid,with the result that absorption of dsRNAs through the mucosa isenhanced. In addition to bile salts and fatty acids, these penetrationenhancers include, for example, sodium lauryl sulfate,polyoxyethylene-9-lauryl ether and polyoxyethylene-20-cetyl ether) (Leeet al., Critical Reviews in Therapeutic Drug Carrier Systems, 1991, p.92); and perfluorochemical emulsions, such as FC-43 (Takahashi et al.,J. Pharm. Pharmacol., 1988, 40, 252).

Fatty acids: Various fatty acids and their derivatives which act aspenetration enhancers include, for example, oleic acid, lauric acid,capric acid (n-decanoic acid), myristic acid, palmitic acid, stearicacid, linoleic acid, linolenic acid, dicaprate, tricaprate, monoolein(1-monooleoyl-rac-glycerol), dilaurin, caprylic acid, arachidonic acid,glycerol 1-monocaprate, 1-dodecylazacycloheptan-2-one, acylcarnitines,acylcholines, C₁-C₁₀ alkyl esters thereof (e.g., methyl, isopropyl andt-butyl), and mono- and di-glycerides thereof (i.e., oleate, laurate,caprate, myristate, palmitate, stearate, linoleate, etc.) (Lee et al.,Critical Reviews in Therapeutic Drug Carrier Systems, 1991, p. 92;Muranishi, Critical Reviews in Therapeutic Drug Carrier Systems, 1990,7, 1-33; El Hariri et al., J. Pharm. Pharmacol., 1992, 44, 651-654).

Bile salts: The physiological role of bile includes the facilitation ofdispersion and absorption of lipids and fat-soluble vitamins (Brunton,Chapter 38 in: Goodman & Gilman's The Pharmacological Basis ofTherapeutics, 9th Ed., Hardman et al. Eds., McGraw-Hill, New York, 1996,pp. 934-935). Various natural bile salts, and their syntheticderivatives, act as penetration enhancers. Thus the term “bile salts”includes any of the naturally occurring components of bile as well asany of their synthetic derivatives. The bile salts of the inventioninclude, for example, cholic acid (or its pharmaceutically acceptablesodium salt, sodium cholate), dehydrocholic acid (sodiumdehydrocholate), deoxycholic acid (sodium deoxycholate), glucholic acid(sodium glucholate), glycholic acid (sodium glycocholate),glycodeoxycholic acid (sodium glycodeoxycholate), taurocholic acid(sodium taurocholate), taurodeoxycholic acid (sodium taurodeoxycholate),chenodeoxycholic acid (sodium chenodeoxycholate), ursodeoxycholic acid(UDCA), sodium tauro-24,25-dihydro-fusidate (STDHF), sodiumglycodihydrofusidate and polyoxyethylene-9-lauryl ether (POE) (Lee etal., Critical Reviews in Therapeutic Drug Carrier Systems, 1991, page92; Swinyard, Chapter 39 In: Remington's Pharmaceutical Sciences, 18thEd., Gennaro, ed., Mack Publishing Co., Easton, Pa., 1990, pages782-783; Muranishi, Critical Reviews in Therapeutic Drug CarrierSystems, 1990, 7, 1-33; Yamamoto et al., J. Pharm. Exp. Ther., 1992,263, 25; Yamashita et al., J. Pharm. Sci., 1990, 79, 579-583).

Chelating Agents: Chelating agents, as used in connection with thepresent invention, can be defined as compounds that remove metallic ionsfrom solution by forming complexes therewith, with the result thatabsorption of dsRNAs through the mucosa is enhanced. With regards totheir use as penetration enhancers in the present invention, chelatingagents have the added advantage of also serving as DNase inhibitors, asmost characterized DNA nucleases require a divalent metal ion forcatalysis and are thus inhibited by chelating agents (Jarrett, J.Chromatogr., 1993, 618, 315-339). Chelating agents of the inventioninclude but are not limited to disodium ethylenediaminetetraacetate(EDTA), citric acid, salicylates (e.g., sodium salicylate,5-methoxysalicylate and homovanilate), N-acyl derivatives of collagen,laureth-9 and N-amino acyl derivatives of beta-diketones (enamines)(Leeet al., Critical Reviews in Therapeutic Drug Carrier Systems, 1991, page92; Muranishi, Critical Reviews in Therapeutic Drug Carrier Systems,1990, 7, 1-33; Buur et al., J. Control Rel., 1990, 14, 43-51).

Non-chelating non-surfactants: As used herein, non-chelatingnon-surfactant penetration enhancing compounds can be defined ascompounds that demonstrate insignificant activity as chelating agents oras surfactants but that nonetheless enhance absorption of dsRNAs throughthe alimentary mucosa (Muranishi, Critical Reviews in Therapeutic DrugCarrier Systems, 1990, 7, 1-33). This class of penetration enhancersinclude, for example, unsaturated cyclic ureas, 1-alkyl- and1-alkenylazacyclo-alkanone derivatives (Lee et al., Critical Reviews inTherapeutic Drug Carrier Systems, 1991, page 92); and non-steroidalanti-inflammatory agents such as diclofenac sodium, indomethacin andphenylbutazone (Yamashita et al., J. Pharm. Pharmacol., 1987, 39,621-626).

Agents that enhance uptake of dsRNAs at the cellular level may also beadded to the pharmaceutical and other compositions of the presentinvention. For example, cationic lipids, such as lipofectin (Junichi etal, U.S. Pat. No. 5,705,188), cationic glycerol derivatives, andpolycationic molecules, such as polylysine (Lollo et al., PCT App WO97/30731) and other peptides, are also known to enhance the cellularuptake of dsRNAs.

Other agents may be utilized to enhance the penetration of theadministered nucleic acids, including glycols such as ethylene glycoland propylene glycol, pyrrols such as 2-pyrrol, azones, and terpenessuch as limonene and menthone.

Carriers

Certain compositions of the present invention also incorporate carriercompounds in the formulation. As used herein, “carrier compound” or“carrier” can refer to a nucleic acid, or analog thereof, which is inert(i.e., does not possess biological activity per se) but is recognized asa nucleic acid by in vivo processes that reduce the bioavailability of anucleic acid having biological activity by, for example, degrading thebiologically active nucleic acid or promoting its removal fromcirculation. The coadministration of a nucleic acid and a carriercompound, typically with an excess of the latter substance, can resultin a substantial reduction of the amount of nucleic acid recovered inthe liver, kidney or other extracirculatory reservoirs, presumably dueto competition between the carrier compound and the nucleic acid for acommon receptor. For example, the recovery of a partiallyphosphorothioate dsRNA in hepatic tissue can be reduced when it iscoadministered with polyinosinic acid, dextran sulfate, polycytidic acidor 4-acetamido-4′isothiocyano-stilbene-2,2′-disulfonic acid (Miyao etal., Antisense Res. Dev., 1995, 5, 115-121 Takakura et al., Antisense &Nucl. Acid Drug Dev., 1996, 6, 177-183.

Excipients

In contrast to a carrier compound, a “pharmaceutical carrier” or“excipient” is a pharmaceutically acceptable solvent, suspending agentor any other pharmacologically inert vehicle for delivering one or morenucleic acids to an animal. The excipient may be liquid or solid and isselected, with the planned manner of administration in mind, so as toprovide for the desired bulk, consistency, etc., when combined with anucleic acid and the other components of a given pharmaceuticalcomposition. Typical pharmaceutical carriers include, but are notlimited to, binding agents (e.g., pregelatinized maize starch,polyvinylpyrrolidone or hydroxypropyl methylcellulose, etc.); fillers(e.g., lactose and other sugars, microcrystalline cellulose, pectin,gelatin, calcium sulfate, ethyl cellulose, polyacrylates or calciumhydrogen phosphate, etc.); lubricants (e.g., magnesium stearate, talc,silica, colloidal silicon dioxide, stearic acid, metallic stearates,hydrogenated vegetable oils, corn starch, polyethylene glycols, sodiumbenzoate, sodium acetate, etc.); disintegrants (e.g., starch, sodiumstarch glycolate, etc.); and wetting agents (e.g., sodium laurylsulphate, etc).

Pharmaceutically acceptable organic or inorganic excipient suitable fornon-parenteral administration which do not deleteriously react withnucleic acids can also be used to formulate the compositions of thepresent invention. Suitable pharmaceutically acceptable carriersinclude, but are not limited to, water, salt solutions, alcohols,polyethylene glycols, gelatin, lactose, amylose, magnesium stearate,talc, silicic acid, viscous paraffin, hydroxymethylcellulose,polyvinylpyrrolidone and the like.

Formulations for topical administration of nucleic acids may includesterile and non-sterile aqueous solutions, non-aqueous solutions incommon solvents such as alcohols, or solutions of the nucleic acids inliquid or solid oil bases. The solutions may also contain buffers,diluents and other suitable additives. Pharmaceutically acceptableorganic or inorganic excipients suitable for non-parenteraladministration which do not deleteriously react with nucleic acids canbe used.

Suitable pharmaceutically acceptable excipients include, but are notlimited to, water, salt solutions, alcohol, polyethylene glycols,gelatin, lactose, amylose, magnesium stearate, talc, silicic acid,viscous paraffin, hydroxymethylcellulose, polyvinylpyrrolidone and thelike.

Pharmaceutical Compositions for the Delivery to the Respiratory Tract

Another aspect of the invention provides for the delivery of iRNA agentsto the respiratory tract, particularly for the treatment of cysticfibrosis. The respiratory tract includes the upper airways, includingthe oropharynx and larynx, followed by the lower airways, which includethe trachea followed by bifurcations into the bronchi and bronchioli.The upper and lower airways are called the conductive airways. Theterminal bronchioli then divide into respiratory bronchioli which thenlead to the ultimate respiratory zone, the alveoli, or deep lung. Theepithelium of the conductive airways is the primary target of inhaledtherapeutic aerosols for delivery of iRNA agents such as alpha-ENaC iRNAagents.

Pulmonary delivery compositions can be delivered by inhalation by thepatient of a dispersion so that the composition, preferably the iRNAagent, within the dispersion can reach the lung where it can, forexample, be readily absorbed through the alveolar region directly intoblood circulation. Pulmonary delivery can be effective both for systemicdelivery and for localized delivery to treat diseases of the lungs.

Pulmonary delivery can be achieved by different approaches, includingthe use of nebulized, aerosolized, micellular and dry powder-basedformulations; administration by inhalation may be oral and or nasal.Delivery can be achieved with liquid nebulizers, aerosol-based inhalers,and dry powder dispersion devices. Metered-dose devices are preferred.One of the benefits of using an atomizer or inhaler is that thepotential for contamination is minimized because the devices are selfcontained. Dry powder dispersion devices, for example, deliver drugsthat may be readily formulated as dry powders. An iRNA composition maybe stably stored as lyophilized or spray-dried powders by itself or incombination with suitable powder carriers. The delivery of a compositionfor inhalation can be mediated by a dosing timing element which caninclude a timer, a dose counter, time measuring device, or a timeindicator which when incorporated into the device enables dose tracking,compliance monitoring, and or dose triggering to a patient duringadministration of the aerosol medicament.

Examples of pharmaceutical devices for aerosol delivery include metereddose inhalers (MDIs), dry powder inhalers (DPIs), and air-jetnebulizers. Exemplary delivery systems by inhalation which can bereadily adapted for delivery of the subject iRNA agents are describedin, for example, U.S. Pat. Nos. 5,756,353; 5,858,784; and PCTapplications WO98/31346; WO98/10796; WO00/27359; WO01/54664;WO02/060412. Other aerosol formulations that may be used for deliveringthe iRNA agents are described in U.S. Pat. Nos. 6,294,153; 6,344,194;6,071,497, and PCT applications WO02/066078; WO02/053190; WO01/60420;WO00/66206. Further, methods for delivering iRNA agents can be adaptedfrom those used in delivering other oligonucleotides (e.g., an antisenseoligonucleotide) by inhalation, such as described in Templin et al.,Antisense Nucleic Acid Drug Dev, 2000, 10:359-68; Sandrasagra et al.,Expert Opin Biol Ther, 2001, 1:979-83; Sandrasagra et al., AntisenseNucleic Acid Drug Dev, 2002, 12:177-81.

The delivery of the inventive agents may also involve the administrationof so called “pro-drugs”, i.e. formulations or chemical modifications ofa therapeutic substance that require some form of processing ortransport by systems innate to the subject organism to release thetherapeutic substance, preferably at the site where its action isdesired; this latter embodiment may be used in conjunction with deliveryof the respiratory tract, but also together with other embodiments ofthe present invention. For example, the human lungs can remove orrapidly degrade hydrolytically cleavable deposited aerosols over periodsranging from minutes to hours. In the upper airways, ciliated epitheliacontribute to the “mucociliary excalator” by which particles are sweptfrom the airways toward the mouth. Pavia, D., “Lung MucociliaryClearance,” in Aerosols and the Lung: Clinical and Experimental Aspects,Clarke, S. W. and Pavia, D., Eds., Butterworths, London, 1984. In thedeep lungs, alveolar macrophages are capable of phagocytosing particlessoon after their deposition. Warheit et al. Microscopy Res. Tech., 26:412-422 (1993); and Brain, J. D., “Physiology and Pathophysiology ofPulmonary Macrophages,” in The Reticuloendothelial System, S. M.Reichard and J. Filkins, Eds., Plenum, New. York., pp. 315-327, 1985.

In preferred embodiments, particularly where systemic dosing with theiRNA agent is desired, the aerosoled iRNA agents are formulated asmicroparticles. Microparticles having a diameter of between 0.5 and tenmicrons can penetrate the lungs, passing through most of the naturalbarriers. A diameter of less than ten microns is required to bypass thethroat; a diameter of 0.5 microns or greater is required to avoid beingexhaled.

Other Components

Compositions of the present invention may additionally contain otheradjunct components conventionally found in pharmaceutical compositions,at their art-established usage levels. Thus, for example, thecompositions may contain additional, compatible, pharmaceutically-activematerials such as, for example, antipruritics, astringents, localanesthetics or anti-inflammatory agents, or may contain additionalmaterials useful in physically formulating various dosage forms of thecompositions of the present invention, such as dyes, flavoring agents,preservatives, antioxidants, opacifiers, thickening agents andstabilizers. However, such materials, when added, should not undulyinterfere with the biological activities of the components of thecompositions of the present invention. The formulations can besterilized and, if desired, mixed with auxiliary agents, e.g.,lubricants, preservatives, stabilizers, wetting agents, emulsifiers,salts for influencing osmotic pressure, buffers, colorings, flavoringsand or aromatic substances and the like which do not deleteriouslyinteract with the nucleic acid(s) of the formulation.

Aqueous suspensions may contain substances which increase the viscosityof the suspension including, for example, sodium carboxymethylcellulose,sorbitol and or dextran. The suspension may also contain stabilizers.

Certain embodiments of the invention provide pharmaceutical combinationsand compositions containing (a) one or more dsRNA agents and (b) one ormore other therapeutic agents which function by a non-RNA interferencemechanism.

Accordingly, the invention includes a combination of an iRNA of thepresent invention with an anti-inflammatory, bronchodilatory,antihistamine, anti-tussive, antibiotic or DNase drug substance, saidepithelial sodium channel blocker and said drug substance being in thesame or different pharmaceutical composition.

Suitable antibiotics include macrolide antibiotics, e.g., tobramycin(TOBI™).

Suitable DNase drug substances include dornase alfa (Pulmozyme™), ahighly-purified solution of recombinant human deoxyribonuclease I(rhDNase), which selectively cleaves DNA. Dornase alfa is used to treatcystic fibrosis.

Other useful combinations of epithelial sodium channel blockers withanti-inflammatory drugs are those with antagonists of chemokinereceptors, e.g., CCR-1, CCR-2, CCR-3, CCR-4, CCR-5, CCR-6, CCR-7, CCR-8,CCR-9 and CCR10, CXCR1, CXCR2, CXCR3, CXCR4, CXCR5, particularly CCR-5antagonists, such as Schering-Plough antagonists SC-351125, SCH-55700and SCH-D; Takeda antagonists, such asN-[[4-[[[6,7-dihydro-2-(4-methyl-phenyl)-5H-benzo-cyclohepten-8-yl]carbonyl]amino]phenyl]-methyl]tetrahydro-N,N-dimethyl-2H-pyran-4-amin-iumchloride (TAK-7701; and CCR-5 antagonists described in U.S. Pat. No.6,166,037 (particularly claims 18 and 19), WO 00/66558 (particularlyclaim 8), WO 00/66559 (particularly claim 9), WO 04/018425 and WO04/026873.

Suitable anti-inflammatory drugs include steroids, in particular,glucocorticosteroids, such as budesonide, beclamethasone dipropionate,fluticasone propionate, ciclesonide or mometasone furoate, or steroidsdescribed in WO 02/88167, WO 02/12266, WO 02/100879, WO 02/00679(especially those of Examples 3, 11, 14, 7, 19, 26, 34, 37, 39, 51, 60,67, 72, 73, 90, 99 and 101), WO 03/35668, WO 03/48181, WO 03/62259, WO03/64445, WO 03/72592, WO 04/39827 and WO 04/66920; non-steroidalglucocorticoid receptor agonists, such as those described in DE10261874, WO 00/00531, WO 02/10143, WO 03/82280, WO 03/82787, WO03/86294, WO 03/104195, WO 03/101932, WO 04/05229, WO 04/18429, WO04/19935 and WO 04/26248; LTD antagonists, such as montelukast andzafirlukast; PDE4 inhibitors, such as cilomilast (Ariflo®GlaxoSmithKline), Roflumilast (Byk Gulden), V-11294A (Napp), BAY19-8004(Bayer), SCH-351591 (Schering-Plough), Arofylline (AlmirallProdesfarma), PD189659/PD168787 (Parke-Davis), AWD-12-281 (Asta Medica),CDC-801 (Celgene), SelCID™ CC-10004 (Celgene), VM554/UM565 (Vernalis),T-440 (Tanabe), KW-4490 (Kyowa Hakko Kogyo), and those disclosed in WO92/19594, WO 93/19749, WO 93/19750, WO 93/19751, WO 98/18796, WO99/16766, WO 01/13953, WO 03/104204, WO 03/104205, WO 03/39544, WO04/000814, WO 04/000839, WO 04/005258, WO 04/018450, WO 04/018451, WO04/018457, WO 04/018465, WO 04/018431, WO 04/0189, WO 04/018450, WO04/018451, WO 04/018457, WO 04/018465, WO 04/019944, WO 04/019945, WO04/045607 and WO 04/037805; adenosine A2B receptor antagonists such asthose described in WO 02/42298; and beta-2 adrenoceptor agonists, suchas albuterol (salbutamol), metaproterenol, terbutaline, salmeterolfenoterol, procaterol, and especially, formoterol, carmoterol andpharmaceutically acceptable salts thereof, and compounds (in free orsalt or solvate form) of formula (I) of WO 0075114, which document isincorporated herein by reference, preferably compounds of the Examplesthereof, especially indacaterol and pharmaceutically acceptable saltsthereof, as well as compounds (in free or salt or solvate form) offormula (I) of WO 04/16601, and also compounds of EP 1440966, JP05025045, WO 93/18007, WO 99/64035, USP 2002/0055651, WO 01/42193, WO01/83462, WO 02/66422, WO 02/70490, WO 02/76933, WO 03/239, WO 03/42160,WO 03/42164, WO 03/72539, WO 03/91204, WO 03/99764, WO 04/16578, WO04/22547, WO 04/32921, WO 04/33412, WO 04/37768, WO 04/37773, WO04/37807, WO 04/39762, WO 04/39766, WO 04/45618, WO 04/46083, WO04/80964, WO 04/108765 and WO 04/108676.

Suitable bronchodilatory drugs include anticholinergic or antimuscarinicagents, in particular, ipratropium bromide, oxitropium bromide,tiotropium salts and CHF 4226 (Chiesi), and glycopyrrolate, but alsothose described in EP 424021, U.S. Pat. No. 3,714,357, U.S. Pat. No.5,171,744, WO 01/04118, WO 02/00652, WO 02/51841, WO 02/53564, WO03/00840, WO 03/33495, WO 03/53966, WO 03/87094, WO 04/018422 and WO04/05285.

Suitable dual anti-inflammatory and bronchodilatory drugs include dualbeta-2 adrenoceptor agonist/muscarinic antagonists such as thosedisclosed in USP 2004/0167167, WO 04/74246 and WO 04/74812.

Suitable antihistamine drug substances include cetirizine hydrochloride,acetaminophen, clemastine fumarate, promethazine, loratidine,desloratidine, diphenhydrarmine and fexofenadine hydrochloride,activastine, astemizole, azelastine, ebastine, epinastine, mizolastineand tefenadine, as well as those disclosed in JP 2004107299, WO03/099807 and WO 04/026841.

Other useful combinations of agents of the invention withanti-inflammatory drugs are those with antagonists of chemokinereceptors, e.g., CCR-1, CCR-2, CCR-3, CCR-4, CCR-5, CCR-6, CCR-7, CCR-8,CCR-9 and CCR10, CXCR1, CXCR2, CXCR3, CXCR4, CXCR5, particularly CCR-5antagonists, such as Schering-Plough antagonists SC-351125, SCH-55700and SCH-D; Takeda antagonists, such asN-[[4-[[[6,7-dihydro-2-(4-methylphenyl)-5H-benzo-cyclohepten-8-yl]carbonyl]amino]phenyl]-methyl]tetrahydro-N,N-dimethyl-2H-pyran-4-amin-iumchloride (TAK-770), and CCR-5 antagonists described in U.S. Pat. No.6,166,037 (particularly claims 18 and 19), WO 00/66558 (particularlyclaim 8), WO 00/66559 (particularly claim 9), WO 04/018425 and WO04/026873.

Other useful additional therapeutic agents may also be selected from thegroup consisting of cytokine binding molecules, particularly antibodiesof other cytokines, in particular a combination with an anti-IL4antibody, such as described in PCT EP2005/00836, an anti-IgE antibody,such as Xolair®, an anti-IL31 antibody, an anti-IL31R antibody, ananti-TSLP antibody, an anti-TSLP receptor antibody, an anti-endoglinantibody, an anti-IL1b antibody or an anti-IL13 antibody, such asdescribed in WO05/007699.

Two or more combined compounds may be used together in a singleformulation, separately, concomitantly or sequentially.

Toxicity and therapeutic efficacy of such compounds can be determined bystandard pharmaceutical procedures in cell cultures or experimentalanimals, e.g., for determining the LD50 (the dose lethal to 50% of thepopulation) and the ED50 (the dose therapeutically effective in 50% ofthe population). The dose ratio between toxic and therapeutic effects isthe therapeutic index and it can be expressed as the ratio LD50/ED50.Compounds which exhibit high therapeutic indices are preferred.

The data obtained from cell culture assays and animal studies can beused in formulating a range of dosage for use in humans. The dosage ofcompositions of the invention lies generally within a range ofcirculating concentrations that include the ED50 with little or notoxicity. The dosage may vary within this range depending upon thedosage form employed and the route of administration utilized. For anycompound used in the method of the invention, the therapeuticallyeffective dose can be estimated initially from cell culture assays. Adose may be formulated in animal models to achieve a circulating plasmaconcentration range of the compound or, when appropriate, of thepolypeptide product of a target sequence (e.g., achieving a decreasedconcentration of the polypeptide) that includes the IC50 (i.e., theconcentration of the test compound which achieves a half-maximalinhibition of symptoms) as determined in cell culture. Such informationcan be used to more accurately determine useful doses in humans. Levelsin plasma may be measured, for example, by high performance liquidchromatography.

In addition to their administration individually or as a plurality, asdiscussed above, the dsRNAs of the invention can be administered incombination with other known agents effective in treatment of ENaCrelated disorders. In any event, the administering physician can adjustthe amount and timing of dsRNA administration on the basis of resultsobserved using standard measures of efficacy known in the art ordescribed herein.

Treatment Methods and Routes of Delivery

A composition that includes an iRNA agent, e.g., an iRNA agent thattargets alpha-ENaC, can be delivered to a subject by a variety of routesto achieve either local delivery to the site of action or systemicdelivery to the subject. Exemplary routes include direct localadministration to the site of treatment, such as the lungs and nasalpassage as well as intravenous, nasal, oral, and ocular delivery. Thepreferred means of administering the iRNA agents of the presentinvention is through direct administration to the lungs and nasalpassage as a liquid, aerosol or nebulized solution.

Formulations for inhalation or parenteral administration are well knownin the art. Such formulation may include sterile aqueous solutions whichmay also contain buffers, diluents and other suitable additives. Forintravenous use, the total concentration of solutes should be controlledto render the preparation isotonic.

The active compounds disclosed herein are preferably administered to thelung(s) or nasal passage of a subject by any suitable means. Activecompounds may be administered by administering an aerosol suspension ofrespirable particles comprised of the active compound or activecompounds, which the subject inhales. The active compound can beaerosolized in a variety of forms, such as, but not limited to, drypowder inhalants, metered dose inhalants, or liquid suspensions. Therespirable particles may be liquid or solid. The particles mayoptionally contain other therapeutic ingredients such as amiloride,benzamil or phenamil, with the selected compound included in an amounteffective to inhibit the reabsorption of water from airway mucoussecretions, as described in U.S. Pat. No. 4,501,729.

The particulate pharmaceutical composition may optionally be combinedwith a carrier to aid in dispersion or transport. A suitable carriersuch as a sugar (i.e., lactose, sucrose, trehalose, mannitol) may beblended with the active compound or compounds in any suitable ratio(e.g., a 1 to 1 ratio by weight).

Particles comprised of the active compound for practicing the presentinvention should include particles of respirable size, that is,particles of a size sufficiently small to pass through the mouth or noseand larynx upon inhalation and into the bronchi and alveoli of thelungs. In general, particles ranging from about 1 to 10 microns in size(more particularly, less than about 5 microns in size) are respirable.Particles of non-respirable size which are included in the aerosol tendto deposit in the throat and be swallowed, and the quantity ofnon-respirable particles in the aerosol is preferably minimized. Fornasal administration, a particle size in the range of 10-500 uM ispreferred to ensure retention in the nasal cavity.

Liquid pharmaceutical compositions of active compound for producing anaerosol may be prepared by combining the active compound with a suitablevehicle, such as sterile pyrogen free water. The hypertonic salinesolutions used to carry out the present invention are preferablysterile, pyrogen-free solutions, comprising from one to fifteen percent(by weight) of the physiologically acceptable salt, and more preferablyfrom three to seven percent by weight of the physiologically acceptablesalt.

Aerosols of liquid particles comprising the active compound may beproduced by any suitable means, such as with a pressure-driven jetnebulizer or an ultrasonic nebulizer. See, e.g., U.S. Pat. No.4,501,729. Nebulizers are commercially available devices which transformsolutions or suspensions of the active ingredient into a therapeuticaerosol mist either by means of acceleration of compressed gas,typically air or oxygen, through a narrow venturi orifice or by means ofultrasonic agitation.

Suitable formulations for use in nebulizers consist of the activeingredient in a liquid carrier, the active ingredient comprising up to40% w/w of the formulation, but preferably less than 20% w/w. Thecarrier is typically water (and most preferably sterile, pyrogen-freewater) or a dilute aqueous alcoholic solution, preferably made isotonic,but may be hypertonic with body fluids by the addition of, for example,sodium chloride. Optional additives include preservatives if theformulation is not made sterile, for example, methyl hydroxybenzoate,antioxidants, flavoring agents, volatile oils, buffering agents andsurfactants.

Aerosols of solid particles comprising the active compound may likewisebe produced with any solid particulate therapeutic aerosol generator.Aerosol generators for administering solid particulate therapeutics to asubject produce particles which are respirable and generate a volume ofaerosol containing a predetermined metered dose of a therapeutic at arate suitable for human administration. One illustrative type of solidparticulate aerosol generator is an insufflator. Suitable formulationsfor administration by insufflation include finely comminuted powderswhich may be delivered by means of an insufflator or taken into thenasal cavity in the manner of a snuff. In the insufflator, the powder(e.g., a metered dose thereof effective to carry out the treatmentsdescribed herein) is contained in capsules or cartridges, typically madeof gelatin or plastic, which are either pierced or opened in situ andthe powder delivered by air drawn through the device upon inhalation orby means of a manually-operated pump. The powder employed in theinsufflator consists either solely of the active ingredient or of apowder blend comprising the active ingredient, a suitable powderdiluent, such as lactose, and an optional surfactant. The activeingredient typically comprises from 0.1 to 100 w/w of the formulation.

A second type of illustrative aerosol generator comprises a metered doseinhaler. Metered dose inhalers are pressurized aerosol dispensers,typically containing a suspension or solution formulation of the activeingredient in a liquefied propellant. During use these devices dischargethe formulation through a valve adapted to deliver a metered volume,typically from 10 to 200 ul, to produce a fine particle spray containingthe active ingredient. Suitable propellants include certainchlorofluorocarbon compounds, for example, dichlorodifluoromethane,trichlorofluoromethane, dichlorotetrafluoroethane and mixtures thereof.The formulation may additionally contain one or more co-solvents, forexample, ethanol, surfactants, such as oleic acid or sorbitan trioleate,antioxidant and suitable flavoring agents.

An iRNA agent can be incorporated into pharmaceutical compositionssuitable for administration. For example, compositions can include oneor more species of an iRNA agent and a pharmaceutically acceptablecarrier. As used herein the language “pharmaceutically acceptablecarrier” is intended to include any and all solvents, dispersion media,coatings, antibacterial and antifungal agents, isotonic and absorptiondelaying agents, and the like, compatible with pharmaceuticaladministration. The use of such media and agents for pharmaceuticallyactive substances is well known in the art. Except insofar as anyconventional media or agent is incompatible with the active compound,use thereof in the compositions is contemplated. Supplementary activecompounds can also be incorporated into the compositions.

Administration can be provided by the subject or by another person,e.g., a caregiver. A caregiver can be any entity involved with providingcare to the human: for example, a hospital, hospice, doctor's office,outpatient clinic; a healthcare worker such as a doctor, nurse, or otherpractitioner; or a spouse or guardian, such as a parent. The medicationcan be provided in measured doses or in a dispenser which delivers ametered dose.

The term “therapeutically effective amount” is the amount present in thecomposition that is needed to provide the desired level of drug in thesubject to be treated to give the anticipated physiological response.

The term “physiologically effective amount” is that amount delivered toa subject to give the desired palliative or curative effect.

The term “pharmaceutically acceptable carrier” means that the carriercan be taken into the lungs with no significant adverse toxicologicaleffects on the lungs.

The term “co-administration” refers to administering to a subject two ormore agents, and in particular two or more iRNA agents. The agents canbe contained in a single pharmaceutical composition and be administeredat the same time, or the agents can be contained in separate formulationand administered serially to a subject. So long as the two agents can bedetected in the subject at the same time, the two agents are said to beco-administered.

The types of pharmaceutical excipients that are useful as carrierinclude stabilizers such as human serum albumin (HSA), bulking agentssuch as carbohydrates, amino acids and polypeptides; pH adjusters orbuffers; salts such as sodium chloride; and the like. These carriers maybe in a crystalline or amorphous form or may be a mixture of the two.

Bulking agents that are particularly valuable include compatiblecarbohydrates, polypeptides, amino acids or combinations thereof.Suitable carbohydrates include monosaccharides such as galactose,D-mannose, sorbose, and the like; disaccharides, such as lactose,trehalose, and the like; cyclodextrins, such as2-hydroxypropyl-.beta.-cyclodextrin; and polysaccharides, such asraffinose, maltodextrins, dextrans, and the like; alditols, such asmannitol, xylitol, and the like. A preferred group of carbohydratesincludes lactose, threhalose, raffinose maltodextrins, and mannitol.Suitable polypeptides include aspartame. Amino acids include alanine andglycine, with glycine being preferred.

Suitable pH adjusters or buffers include organic salts prepared fromorganic acids and bases, such as sodium citrate, sodium ascorbate, andthe like; sodium citrate is preferred.

Dosage

An iRNA agent can be administered at a unit dose less than about 75 mgper kg of bodyweight, or less than about 70, 60, 50, 40, 30, 20, 10, 5,2, 1, 0.5, 0.1, 0.05, 0.01, 0.005, 0.001, or 0.0005 mg per kg ofbodyweight, and less than 200 nmol of iRNA agent (e.g., about 4.4×10¹⁶copies) per kg of bodyweight, or less than 1500, 750, 300, 150, 75, 15,7.5, 1.5, 0.75, 0.15, 0.075, 0.015, 0.0075, 0.0015, 0.00075, 0.00015nmol of iRNA agent per kg of bodyweight. The unit dose, for example, canbe administered by injection (e.g., intravenous or intramuscular,intrathecally, or directly into an organ), an inhaled dose, or a topicalapplication.

The dosage can be an amount effective to treat or prevent a disease ordisorder. It can be given prophylactically or as the primary or a partof a treatment protocol.

In one embodiment, the unit dose is administered less frequently thanonce a day, e.g., less than every 2, 4, 8 or 30 days. In anotherembodiment, the unit dose is not administered with a frequency (e.g.,not a regular frequency). For example, the unit dose may be administereda single time. Because iRNA agent mediated silencing can persist forseveral days after administering the iRNA agent composition, in manyinstances, it is possible to administer the composition with a frequencyof less than once per day, or, for some instances, only once for theentire therapeutic regimen.

In one embodiment, a subject is administered an initial dose, and one ormore maintenance doses of an iRNA agent, e.g., a double-stranded iRNAagent, or siRNA agent, (e.g., a precursor, e.g., a larger iRNA agentwhich can be processed into an siRNA agent, or a DNA which encodes aniRNA agent, e.g., a double-stranded iRNA agent, or siRNA agent, orprecursor thereof). The maintenance dose or doses are generally lowerthan the initial dose, e.g., one-half less of the initial dose. Amaintenance regimen can include treating the subject with a dose ordoses ranging from 0.01 to 75 mg/kg of body weight per day, e.g., 70,60, 50, 40, 30, 20, 10, 5, 2, 1, 0.5, 0.1, 0.05, 0.01, 0.005, 0.001, or0.0005 mg per kg of body weight per day. The maintenance doses arepreferably administered no more than once every 5, 10, or 30 days.Further, the treatment regimen may last for a period of time which willvary depending upon the nature of the particular disease, its severityand the overall condition of the patient. In preferred embodiments thedosage may be delivered no more than once per day, e.g., no more thanonce per 24, 36, 48, or more hours, e.g., no more than once every 5 or 8days. Following treatment, the patient can be monitored for changes inhis condition and for alleviation of the symptoms of the disease state.The dosage of the compound may either be increased in the event thepatient does not respond significantly to current dosage levels, or thedose may be decreased if an alleviation of the symptoms of the diseasestate is observed, if the disease state has been ablated, or ifundesired side-effects are observed.

The effective dose can be administered in a single dose or in two ormore doses, as desired or considered appropriate under the specificcircumstances. If desired to facilitate repeated or frequent infusions,implantation of a delivery device, e.g., a pump, semi-permanent stent(e.g., intravenous, intraperitoneal, intracisternal or intracapsular),or reservoir may be advisable.

Following successful treatment, it may be desirable to have the patientundergo maintenance therapy to prevent the recurrence of the diseasestate, wherein the compound of the invention is administered inmaintenance doses, ranging from 0.001 g to 100 g per kg of body weight(see U.S. Pat. No. 6,107,094).

The concentration of the iRNA agent composition is an amount sufficientto be effective in treating or preventing a disorder or to regulate aphysiological condition in humans. The concentration or amount of iRNAagent administered will depend on the parameters determined for theagent and the method of administration, e.g. nasal, buccal, orpulmonary. For example, nasal formulations tend to require much lowerconcentrations of some ingredients in order to avoid irritation orburning of the nasal passages. It is sometimes desirable to dilute anoral formulation up to 10-100 times in order to provide a suitable nasalformulation.

Certain factors may influence the dosage required to effectively treat asubject, including but not limited to the severity of the disease ordisorder, previous treatments, the general health and or age of thesubject, and other diseases present. It will also be appreciated thatthe effective dosage of an iRNA agent such as an siRNA used fortreatment may increase or decrease over the course of a particulartreatment. Changes in dosage may result and become apparent from theresults of diagnostic assays. For example, the subject can be monitoredafter administering an iRNA agent composition. Based on information fromthe monitoring, an additional amount of the iRNA agent composition canbe administered.

Dosing is dependent on severity and responsiveness of the diseasecondition to be treated, with the course of treatment lasting fromseveral days to several months, or until a cure is effected or adiminution of disease state is achieved. Optimal dosing schedules can becalculated from measurements of drug accumulation in the body of thepatient. Persons of ordinary skill can easily determine optimum dosages,dosing methodologies and repetition rates. Optimum dosages may varydepending on the relative potency of individual compounds, and cangenerally be estimated based on EC50s found to be effective in in vitroand in vivo animal models as described above.

iRNA agents of the present invention as described herein may be usefulin the treatment and (where appropriate) in the prevention of any one ofthe following diseases/disorders;

Cystic fibrosis, Liddles syndrome, renal insufficiency, hypertension,electrolyte imbalances.

In particular in some embodiments, iRNA agents of the invention may beused to treat and or prevent adverse clinical manifestations of thesediseases/disorders.

The invention is further illustrated by the following examples, whichshould not be construed as further limiting.

EXAMPLES Source of Reagents

Where the source of a reagent is not specifically given herein, suchreagent may be obtained from any supplier of reagents for molecularbiology at a quality/purity standard for application in molecularbiology.

Example 1 Selection of Sequences

In order to identify therapeutic siRNAs to downmodulate expression ofthe alpha subunit of the epithelial sodium channel ENaC (α-ENaC),screening sets were defined based on a bioinformatic analysis. The keydrivers for the design of the screening set were predicted specificityof the siRNAs against the transcriptome of the relevant species. For theidentification of alpha-ENaC siRNAs and an efficient delivery system athree pronged approach was used: Rat was selected as the test species toaddress silencing efficacy in vivo after intratracheal delivery, guineapig was selected as the disease model organism to demonstrate thatalpha-ENaC mRNA reduction results in a measurable functional effect. Thetherapeutic siRNA molecule has to target human alpha-ENaC as well as thealpha-ENaC sequence of at least one toxicology-relevant species, in thiscase, rhesus monkey.

Initial analysis of the relevant alpha-ENaC mRNA sequence revealed fewsequences can be identified that fulfil the specificity requirements andat the same time target alpha-ENaC mRNA in all relevant species.Therefore it was decided to design independent screening sets for thetherapeutic siRNA and for the surrogate molecules to be tested in therelevant disease model (Tables 1A, 1B, 1C and 1D).

All siRNAs recognize the human alpha-ENaC sequence, as a human cellculture system was selected for determination of in vitro activity(H441, see below). Therefore all siRNAs can be used to target humanalpha-ENaC mRNA in a therapeutic setting.

The therapeutic screening sets were designed to contain only siRNAsequences that are fully complementary to the human and rhesus monkeyalpha-ENaC sequences.

Design and in Silico Selection of siRNAs Targeting Alpha-ENaC (SCNN1A)

siRNA design was carried out to identify siRNAs for the four previouslydefined sets (see above):

a) “Initial screening set”

b) “Extended screening set”

c) “In vivo surrogate set for rat”

d) “In vivo surrogate set for guinea pig”

Initial Screening Set

The aim for in silico selection of an initial screening set was toidentify siRNAs specifically targeting human alpha-ENaC, as well as itsrhesus monkey ortholog. The human target mRNA (NM_(—)001038.4) wasdownloaded from NCBI resource(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=nucleotide)during the complete siRNA selection procedure. In order to identify thealpha-ENaC rhesus (Macaca mulatta) ortholog, the human sequence was usedin a blastn search at Baylor College of Medicine(http://www.hgsc.bcm.tmc.edu/blast/?organism=Mmulatta) against Mmulattacontigs as of 2004 10 01. All hit regions were extracted and assembledby the CAP assembly tool to generate a first assembly sequence. Further,a BLAST search was performed with the human sequence at UCSC(http://genome.ucsc.edu/cgi-bin/hgBlat?command=start&org=Rhesus&db=rheMac2&hgsid=84859356)against Rhesus freeze 12 Mar. 2005. The scaffold hit 84554 wasdownloaded and used together with the first assembly sequence by CAP togenerate the final consensus sequence for rhesus alpha-ENaC.

Following extraction of all overlapping 19mer sequences out of the humanmRNA, conserved 19mers were identified that had identical sequences inthe assembled rhesus consensus sequence. Those 19mer sequences weredefined as the pool of human-rhesus cross-reactive siRNA (sense)sequences, represented by 1185 19mers.

The corresponding antisense sequences were generated and tested forspecificity in human. For this, their predicted potential forinteracting with irrelevant target mRNAs (off-target potential) wastaken as parameter. Sequences with low off-target potential were definedas preferable and predicted to be more specific.

For further selection, candidate siRNAs were ranked according to theirpredicted potential for interacting with other host sequences (here,without limitation, human). siRNAs with low off-target potential areassumed to be more specific in vivo. For predicting siRNA-specificoff-target potential, the following assumptions were made:

-   -   1) off-target potential of a strand can be deduced from the        number and distribution of mismatches to an off-target    -   2) the most relevant off-target, that is the gene predicted to        have the highest probability to be silenced due to tolerance of        mismatches, determines the off-target potential of the strand    -   3) positions 2 to 9 (counting 5 to 3′) of a strand (seed region)        may contribute more to off-target potential than rest of        sequence (that is non-seed and cleavage site region) (Haley, B.,        and Zamore, P. D., Nat Struct Mol. Biol. 2004, 11:599).    -   4) positions 10 and 11 (counting 5′ to 3′) of a strand (cleavage        site region) may contribute more to off-target potential than        non-seed region (that is positions 12 to 18, counting 5′ to 3′)    -   5) positions 1 and 19 of each strand are not relevant for        off-target interactions    -   6) off-target potential can be expressed by the off-target score        of the most relevant off-target, calculated based on number and        position of mismatches of the strand to the most homologous        region in the off-target gene considering assumptions 3 to 5    -   7) assuming potential abortion of sense strand activity by        internal modifications introduced, only off-target potential of        antisense strand will be relevant

To identify potential off-target genes, 19mer antisense sequences weresubjected to a homology search against publicly available human mRNAsequences, assumed to represent the human comprehensive transcriptome.

To this purpose, fastA (version 3.4) searches were performed with all19mer sequences against a human RefSeq database (available version fromftp://ftp.ncbi.nih.gov/refseq/ on Nov. 18, 2005). FastA search wasexecuted with parameters-values-pairs—f 30-g 30 in order to take intoaccount the homology over the full length of the 19mer without any gaps.In addition, in order to ensure the listing of all relevant off-targethits in the fastA output file the parameter—E 15000 was used.

The search resulted in a list of potential off-targets for each inputsequence listed by descending sequence homology over the complete 19mer.

To rank all potential off-targets according to assumptions 3 to 5, andby this identify the most relevant off-target gene and its off-targetscore, fastA output files were analyzed by a perl script.

The script extracted the following off-target properties for each 19merinput sequence and each off-target gene to calculate the off-targetscore:

Number of mismatches in non-seed region

Number of mismatches in seed region

Number of mismatches in cleavage site region

The off-target score was calculated by considering assumptions 3 to 5 asfollows:

Off-target score=number of seed mismatches*10+number of cleavage sitemismatches*1.2+number of non-seed mismatches*1

The most relevant off-target gene for each 19mer sequence was defined asthe gene with the lowest off-target score. Accordingly, the lowestoff-target score was defined as representative for the off-targetpotential of each siRNA, represented by the 19mer antisense sequenceanalyzed.

Calculated off-target potential was used as sorting parameter(descending by off-target score) in order to generate a ranking for allhuman-rhesus cross-reactive siRNA sequences.

An off-target score of 3 or more was defined as prerequisite for siRNAselection, whereas all sequences containing 4 or more G's in a row(poly-G sequences) were excluded, leading to selection of a total of 152siRNAs targeting human and rhesus ENaC alpha (see Table 1a).

Extended Screening Set

The aim for in silico selection of the extended screening set was toidentify all further siRNAs targeting human alpha-ENaC with sufficientspecificity, that were excluded from the initial set due to missingcross-reactivity to rhesus. The remaining sequences from the pool of19mers derived from human alpha-ENaC that have not been analyzed beforewere taken and the corresponding antisense sequences were generated. Themost relevant off-target gene and its corresponding off-target scoreswere calculated as described in section “Initial screening set”.

For determining cross-reactivity to mouse and guinea pig (Caviaporcellus/cobya), alpha-ENaC sequences of these species were downloadedfrom NCBI nucleotide database 1 (accession numbers NM_(—)011324.1 andAF071230 (full length)/DQ109811 (partial cds), respectively). The twoguinea pig sequences were used to generate aguinea pig alpha-ENaCconsensus sequence. Every human 19mer sequence was tested for presencein the mouse and guinea pig sequences. Positive sequences were assignedto the pool of human-mouse cross-reactive siRNA (sense) sequences, orhuman-guinea pig cross-reactive siRNA (sense) sequences. After exclusionof all poly-G sequences, sequences were selected with off-target scoresof 3 or more as well as those with off-target scores of 2.2 or 2.4 andcross-reactivity to mouse, rhesus or guinea pig. The total number ofsiRNAs in the extended screening pool was 3 (see Table 1b).

In Vivo Rat Surrogate Set

The aim for in silico selection of the in vivo rat surrogate set was toidentify all siRNAs targeting human and rat alpha-ENaC with sufficientspecificity in rat. For identification of human-rat cross-reactivesiRNAs, rat alpha-ENaC mRNA sequence was downloaded from NCBI nucleotidedatabase (accession number, NM_(—)031548.2), and all sequences out ofthe pool of human 19mers were tested for presence in the rat sequence,representing the pool of human-rat cross-reactive siRNA (sense)sequences.

The corresponding antisense sequences were generated and tested forspecificity in rat. For this, the most relevant off-target gene in ratand its corresponding off-target scores were calculated as described insection “Initial screening set” using the rat mRNA set (RefSeq database)instead of the human transcripts. After exclusion of all poly-Gsequences, a ranking was generated considering the rat off-target scorein first priority and the human off-target score with second priority.Those 48 sequences from the top of the list were finally selectedrepresenting the in vivo rat surrogate set (see Table 1c).

In Vivo Guinea Pig Surrogate Set

The aim for in silico selection of the in vivo guinea pig surrogate setwas to identify all siRNAs targeting human and guinea pig alpha-ENaCthat have not been selected in previous sets. The remaining siRNAs ofthe previously determined set of human-guinea pig cross-reactive siRNA(sense) sequences were ranked according to human off-target scores. Thetop 63 sequences (excluding poly-G sequences) were selected,representing the in vivo guinea pig surrogate set (see Table 1d).

Example 2 siRNA Synthesis

Synthesis of Nucleotides Comprising Natural Bases

As the siRNAs from the screening sets are all potentially intended forin vivo administration, siRNAs were synthesised with a modificationstrategy that protects the siRNAs from degradation by endo- andexonucleases in a biological environment. In this strategy, the 3′-endsof both strands are protected from a 3′->5′-exonucleotitic activity by aphosphorothioate linkage between the two last nucleobases at the 3′-end.In order to inhibit endo-nucleolytic degradation of the siRNA allpyrimidines in the sense strand of the siRNA were replaced with thecorresponding 2′-O-methyl-modified ribonucleotide. To reduce the numberof modifications in the antisense strand, which is the more activestrand and therefore more sensitive to modifications, we only modifiedthe pyrimidines in the context of previously identified major nucleasecleavage sites with 2′-O-methyl groups. The major cleavage sites are thefollowing two sequence motifs: 5′-UA-3′ and 5′-CA-3′.

Since it has also been considered to use siRNAs in formulations thatpotentially protect the RNAs from the nucleolytic biological environmentin the lung, the same set of siRNAs were also synthesized without anyprotection from endonucleolytic degradation.

Where the source of a reagent is not specifically given herein, suchreagent may be obtained from any supplier of reagents for molecularbiology at a quality/purity standard for application in molecularbiology.

Single-stranded RNAs were produced by solid phase synthesis on a scaleof 1 μmole using an Expedite 8909 synthesizer (Applied Biosystems,Applera Deutschland GmbH, Darmstadt, Germany) and controlled pore glass(CPG, 500 Å, Proligo Biochemie GmbH, Hamburg, Germany) as solid support.RNA and RNA containing 2′-O-methyl nucleotides were generated by solidphase synthesis employing the corresponding phosphoramidites and2′-O-methyl phosphoramidites, respectively (Proligo Biochemie GmbH,Hamburg, Germany). These building blocks were incorporated at selectedsites within the sequence of the oligoribonucleotide chain usingstandard nucleoside phosphoramidite chemistry such as described inCurrent protocols in nucleic acid chemistry, Beaucage, S. L. et al.(Edrs.), John Wiley & Sons, Inc., New York, N.Y., USA. Phosphorothioatelinkages were introduced by replacement of the iodine oxidizer solutionwith a solution of the Beaucage reagent (Chruachem Ltd, Glasgow, UK) inacetonitrile (1%). Further ancillary reagents were obtained fromMallinckrodt Baker (Griesheim Germany).

Deprotection and purification of the crude oligoribonucleotides by anionexchange HPLC were carried out according to established procedures.Yields and concentrations were determined by UV absorption of a solutionof the respective RNA at a wavelength of 260 nm using a spectralphotometer (DU 640B, Beckman Coulter GmbH, Unterschleiβheim, Germany).Double stranded RNA was generated by mixing an equimolar solution ofcomplementary strands in annealing buffer (20 mM sodium phosphate, pH6.8; 100 mM sodium chloride), heated in a water bath at 85-90° C. for 3minutes and cooled to room temperature over a period of 3-4 hours. Theannealed RNA solution was diluted to a concentration of 50 μmole doublestranded RNA/L and stored at −20° C. until use.

Example 3 siRNA Testing In Vitro

The ability of the iRNA agents to inhibit expression of alpha-ENaC wastested in human cell lines in vitro, or in rats in vivo. The iRNA agentis transfected into the cells, e.g., by transfection, allowed to act onthe cells for a certain time, e.g., 24 hours, and levels of alpha-ENaCmRNA were determined by branched-DNA analysis. Alternatively, the iRNAagent is administered in vivo via the intratracheal route and theinhibition of alpha-ENaC mRNA expression determined by branched-DNAanalysis on the target organ. Complementing these direct assays, wetested the inhibition of target gene expression by RNAi agents foralpha-ENaC mRNA recombinantly expressed in mammalian host cells.

Cell Lines

H441 cells were obtained from the American Type Culture Collection(ATCC-Number: HTB-174, LCG Promochem GmbH, Wesel, Germany) and weregrown in RPMI 1640, 10% fetal calf serum 100 u penicillin/100 μg/mLstreptomycin, 2 mM L-glutamine, 10 nM Hepes and 1 mM Sodium-Pyruvate(all from Biochrom AG, Berlin, Germany) at 37° C. under a 5% CO₂/95% airatmosphere.

Primary human bronchial epithelial cells were obtained from Cambrex (Cat# CC-2540) and were routinely grown in BEGM media with singlequots(Cambrex Cat # CC-3170 minus tri-iodothreonine). For polarisation andgrowth at air liquid interface the cells were grown in a 1:1 mixture ofBFGM:DMEM supplemented with 4.5 g/L D-Glucose (Gibco BRL Cat #41965-039) and supplemented with singlequots (Cambrex Cat # CC-4175), asabove but minus the tri-iodothreonine and GA1000 aliquots and in thepresence of 50 μg/mL Gentamycin (Gibco Brl Cat # 10131-015). As cellswere maintained in serum-free media, trypsin neutralisation solution wasused during passaging steps (Cambrex Cat # CC-5002). For polarisationand culture at air-liquid interface the cells were grown onsemipermeable (0.4 micron) polycarbonate supports (Corning Costar Cat #3407 #3460) and cultured throughout at 37° C. under a 5% CO₂/95% airatmosphere.

Cos-1 African green monkey kidney cells (ATCC #CRL-1650) were grown inDulbecco's MEM, 4.5 g/L glucose, 10% fetal bovine serum, 2 mML-glutamine, 1.5 g/L sodium bicarbonate (Gibco BRL), 100 upenicillin/100 μg/mL streptomycin.

Example 3.1 In Vitro Screen for Active Alpha-ENaC siRNAs and IC50Determination in H441

One day prior to transfection, ENaC-alpha expression was induced in H441cells (ATCC-Number: HTB-174, LCG Promochem GmbH, Wesel, Germany) byadding 100 nM of dexamthasone. Directly before transfection, cells wereseeded at 1.5×10⁴ cells/well on 96-well plates (Greiner Bio-One GmbH,Frickenhausen, Germany) in 75 μL of growth medium (RPMI 1640, 10% fetalcalf serum, 100 u penicillin/100 μl/ml streptomycin, 2 mM L-glutamine,10 nM Hepes and 1 mM Sodium-Pyruvate, all from Biochrom AG, Berlin,Germany). Transfections were performed in quadruplicates. For each well0.5 μL Lipofectamine2000 (Invitrogen GmbH, Karlsruhe, Germany) weremixed with 12 μL Opti-MEM (Invitrogen) and incubated for 15 min at roomtemperature. For the siRNA concentration being 50 nM in the 100 μLtransfection volume, 1 μL of a 5 μM siRNA were mixed with 11.5 μLOpti-MEM per well, combined with the Lipofectamine2000-Opti-MEM mixtureand again incubated for 15 minutes at room temperature.siRNA-Lipofectamine2000-complexes were applied completely (25 μL eachper well) to the cells and cells were incubated for 24 h at 37° C. and5% CO₂ in a humidified incubator (Heraeus GmbH, Hanau).

Cells were harvested by applying 50 μL of lysis mixture (content of theQuantiGene bDNA-kit from Genospectra, Fremont, USA) to each wellcontaining 100 μL of growth medium and were lysed at 53° C. for 30 min.Afterwards, 50 μL of the lysates were incubated with probesets specificto human ENaC-alpha and human GAPDH (sequence of probesets see below)and proceeded according to the manufacturer's protocol for QuantiGene.In the end chemoluminescence was measured in a Victor2-Light (PerkinElmer, Wiesbaden, Germany) as RLUs (relative light units) and valuesobtained with the hENaC probeset were normalized to the respective GAPDHvalues for each well. Values obtained with siRNAs directed againstENaC-alpha were related to the value obtained with an unspecific siRNA(directed against HCV) which was set to 100%. The percentage residualexpression of alpha-ENaC for siRNA examples is shown in Tables 1A-1D.

Effective siRNAs from the screen were further characterized by doseresponse curves. Transfections of dose response curves were performed atthe following concentrations: 100 mM, 16.7 nM, 2.8 nM, 0.46 nM, 77picoM, 12.8 picoM, 2.1 picoM, 0.35 picoM, 59.5 fM, 9.9 fM and mock (nosiRNA) and diluted with Opti-MEM to a final concentration of 12.5 μlaccording to the above protocol. Data analysis was performed usingMicrosoft Excel add-in software XL-fit 4.2 (IDBS, Guildford, Surrey, UK)and applying the sigmoidal model number 606.

SEQ. FPL Name Members Function Sequence ID.NO: Probesets: humanalpha-ENaC: hENAC001 .235.255.CE CEgtctgtccagggtttccttccTTTTTctcttggaaagaaagt 1645 hENAC002 .274.293.CE CEactgccattcttggtgcagtTTTTTctcttggaaagaaagt 1646 hENAC003 .344.367.CE CEctctcctggaagcaggagtgaataTTTTTctcttggaaagaaagt 1647 hENAC004 .391.411.CECE gccgcggatagaagatgtaggTTTTTctcttggaaagaaagt 1648 hENAC005 .501.521.CECE gcacttggtgaaacagcccagTTTTTctcttggaaagaaagt 1649 hENAC006 .539.560.CECE agcagagagctggtagctggtcTTTTTctcttggaaagaaagt 1650 hENAC007 .256.273.LELE cgccataatcgcccccaaTTTTTaggcataggacccgtgtct 1651 hENAC008 .368.390.LELE cacagccacactccttgatcatgTTTTTaggcataggacccgtgtct 1652 hENAC009.412.431.LE LE ggagcttatagtagcagtaccccTTTTTaggcataggacccgtgtct 1653hENAC010 .455.477.LE LE ggagcttatagtagcagtaccccTTTTTaggcataggacccgtgtct1654 hENAC011 .522.538.LE LE acgctgcatggcttccgTTTTTaggcataggacccgtgtct1655 hENAC012 .561.580.LE LEgagggccatcgtgagtaaccTTTTTaggcataggacccgtgtct 1656 hENAC013 .214.234.BLBL Tcatgctgatggaggtctcca 1657 hENAC014 .294.318.BL BLGgtaaaggttctcaacaggaacatc 1658 hENAC015 .319.343.BL BLCacacctgctgtgtgtactttgaag 1659 hENAC016 .432.454.BL BLCaggaactgtgctttctgtagtc 1660 hENAC017 .478.500.BL BLGtggtctgaggagaagtcaacct 1661 hENAC018 .581.599.BL BL Ccattcctgggatgtcacc1662 human GAPDH: hGAP001 AG261085. CEgaatttgccatgggtggaatTTTTTctcttggaaagaaagt 1663 252.271.CE hGAP002AF261085. CE ggagggatctcgctcctggaTTTTTctcttggaaagaaagt 1664 333.352.CEhGAP003 AF261085. CE ccccagccttctccatggtTTTTTctcttggaaagaaagt 1665413.431.CE hGAP004 AF261085. CE gctcccccctgcaaatgagTTTTTctcttggaaagaaagt1666 432.450.CE hGAP005 AF261085. LEagccttgacggtgccatgTTTTTaggcataggacccgtgtct 1667 272.289.LE hGAP006AF261085. LE gatgacaagcttcccgttctcTTTTTaggcataggacccgtgtct 1668290.310.LE hGAP007 AF261085. LEagatggtgatgggatttccattTTTTTaggcataggacccgtgtct 1669 311.332.LE hGAP008AF261085. LE gcatcgccccacttgattttTTTTTaggcataggacccgtgtct 1670353.372.LE hGAP009 AF261085. LEcacgacgtactcagcgccaTTTTTaggcataggacccgtgtct 1671 373.391.LE hGAP010AF261085. LE ggcagagatgatgacccttttgTTTTTaggcataggacccgtgtct 1672451.472.LE hGAP011 AF261085. BL Ggtgaagacgccagtggactc 1673 392.412.BL

The IC₅₀s for siRNA examples is shown in Table 2A and 2B.

Example 3.2 Transient Alpha-ENaC Knockdown in a Primary Human BronchialEpithelial Model

Human bronchial epithelial cells (donor reference 4F1499) were plated in24-well plates at 1×10⁵ cells per well in 0.5 mL growth medium one daybefore transfection. The cells were 70% confluent on the day of siRNAtransfection.

Each siRNA was resuspended at 100 nM in 1 mL of Optimem I (Invitrogen)and in a separate tube, Lipofectamine 2000 (Invitrogen) was diluted to 6μL/mL in Optimem, giving an amount sufficient for transfection of fourreplicates in a 24-well plate. After 5 minutes at room temperature, themixtures were combined to give the desired final concentration of 50 nMsiRNA and 3 μL/mL Lipofectamine 2000. The transfection mixture wasincubated for a further 20 minutes at room temperature and 420 μL of thesiRNA/reagent complex was added to each well as dictated by theexperimental design. Plates were gently rocked to ensure complete mixingand then incubated at 37° C. in an incubator at 5% CO₂/95% air for 4hours. Subsequently, the transfection mixture was aspirated and thecells were returned to normal culture conditions for a further 20 hours.

Cell lysates were prepared for branched-DNA analysis. A 2:1 medium:lysisbuffer (Panomics) mixture was prepared and cells were lysed in 200 μL at53° C. for 30 minutes. After a visual check for complete lysis, the celllysates were stored at −80° C. for subsequent analysis. Branched-DNAanalysis was performed as described above, with alpha-ENaC expressionnormalized against GAPDH. The branched DNA analysis protocol useddiffers from that above only in that 20 μL of sample was applied to eachwell in this case.

Table 2C shows the alpha-ENaC expression in primary HBEC for siRNAexamples.

Example 3.3 In Vitro Inhibition of Exogenously Expressed ClonedCynomolgous Alpha-ENaC Gene Expression for Selected RNAi Agents in Cos-1Cells

Cloning of the Cynomolgous Alpha-ENaC Sequence

Primer sequences for amplification of 5′-UTR and CDS (nucleotides shownin brackets correspond to the Mocaca mulatta (Rhesus monkey) α-ENaC cDNAsequence):

(SEQ.I.D.NO:1674) P745: 5′-CTCCATGTTCTGCGGCCGCGGATAGAAG-3′ (nt 1427)(SEQ.I.D.NO:1675) P733: 5′-CCGGCCGGCGGGCGGGCT-3′ (nt 1)(SEQ.I.D.NO:1676) P734: 5′-CTCCCCAGCCCGGCCGCT-3′ (nt 17)(SEQ.I.D.NO:1677) P735: 5′-GGCCGCTGCACCTGTAGGG-3′ (nt 28)

Primer sequences for amplification of CDS and 3′-UTR:

(SEQ.I.D.NO:1678) P737: 5′-ATGGAGTACTGTGACTACAGG-3′ (nt 1422)(SEQ.I.D.NO:1679) P740: 5′-TTGAGCATCTGCCTACTTG-3′ (nt 3113)

Primer sequences for amplification of internal part of CDS:

(SEQ.I.D.NO:1679) P713: 5′-ATGGATGATGGTGGCTTTAACTTGCGG-3′ (nt 1182)(SEQ.I.D.NO:1680) P715: 5′-TCAGGGCCCCCCCAGAGG-3′ (nt 2108)

Cynomolgus (Macaca fascicularis) lung total RNA (#R1534152-Cy-BC) waspurchased from BioCat (Germany). Synthesis of cDNA was performed usingthe SuperScript III First Strand Synthesis System (Invitrogen).Synthesis of cDNA was performed using either random hexamers or oligo dTprimers. In addition, cynomolgus lung first strand cDNA was alsopurchased from BioCat/#C1534160-Cy-BC). For PCR amplification, theAdvantage 2 PCR kit (#K1910-1, Clontech) was used. Amplification of the5′-UTR and parts of the CDS was performed using P745 and a equimolarmixture of P733, P734 and P735. For PCR amplification of the CDS and3′-UTR, primers P737 and P740 were used. The primers P713 and P715 wereused for amplification of parts of the CDS.

All PCR products were analysed by agarose gel electrophoresis and thencloned into the pCR2.1 vector using the TOPO TA cloning kit (Invitrogen)in TOP10 bacteria. Clones were then picked and DNA was isolated usingthe Qiagen Miniprep kit. After restriction enzyme digest with EcoRI andanalysis by agarose gel electrophoresis, DNA from correct clones weresubjected to sequencing.

The sequences were then aligned with the α-ENaC cDNA sequence of Rhesusmonkey, and sequences of the individual clones were aligned with eachother. The full-length cynomolgus alpha-ENaC cDNA was then cloned bydigestion of the 5′-part (5′-UTR and CDS, clone 55) with EcoR I and NotI, digestion of the middle part of the CDS by Not I and BstE II (clone15), and the 3′-part (CDS and 3′-UTR) by BstE II and EcoR V(clone 80).The digested DNA fragments were then subcloned into pcDNA3.1, digestedwith EcoR I and EcoR V. The full-length cynomolgus alpha-ENaC cDNA inpcDNA3.1 was then subjected to full-length sequencing (Ingenetix,Vienna, Austria). The cynomolgus alpha-ENaC cDNA sequence corresponds tont 28-3113 of the Rhesus alpha-ENaC cDNA sequence. Finally thecynomolgus alpha-ENaC cDNA was then excised from pcDNA3.1-cynomolgusalpha-ENaC by digestion with BamHI and EcoR V and subcloned into thevector pXOON. The plasmid map is illustrated in FIG. 1. Table 3B andTable 3A, respectively depict the protein (SEQ. I.D. NO: 1681) and DNA(SEQ. I.D. NO: 1682) sequence of cynomolgous alpha-ENaC.

Transfections:

COS-1 cells were seeded at 6×10⁴ cells/well on 24 well plates each in0.5 mL of growth medium. One day after seeding the cells wereco-transfected with the pXOON cynomolgous alpha-ENaC expression plasmidand the indicated siRNA. For each well, 4 ng of alpha-ENaC expressionplasmid and 600 ng carrier plasmid (pNFAT-luc) were co-transfected withthe relevant siRNA (final concentration 45 nM) using X-treme genetransfection reagent (Roche) at 3.75 μL/well in a total volume of 720μL/well Opti-MEM (Invitrogen) as described below.

Transfections were performed in triplicate for each sample. PlasmidsiRNA mastermixes (each for 3.5 wells) were prepared as follows: 14 ngalpha-ENaC expression plasmid, 2.1 μg carrier plasmid and 112 pmoles ofrelevant siRNA in a total volume 210 μL (Opti-MEM). A lipid mastermixwas prepared for the whole transfection (105 μL lipid plus 1575 μLOpti-MEM for eight triplicate transfection samples). Plasmid siRNA andlipid were mixed in equal volume to give a total volume of 420 μLtransfection mix per triplicate sample (3.5×). Following a 20 minuteincubation at room temperature, 120 μL of the relevant transfection mixwas added to each well of cells in a final transfection volume of 720 μL(Opti-MEM). Cells were transfected for 24 hours at 37° C. and 5% CO₂ ina humidified incubator (Heraeus GmbH, Hanau, Germany) and harvested forbranched-DNA analysis.

Cell lysates were prepared for branched DNA analysis. A 2:1 medium:lysisbuffer (Panomics) mixture was prepared and cells were lysed in 200 μL at53° C. for 30 minutes. After a visual check for complete lysis, the celllysates were stored at −80° C. for subsequent analysis. Branched-DNAanalysis was performed as described above, with cyno alpha-ENaCexpression normalized against eGFP from the expression plasmid. Thebranched-DNA analysis protocol used differs from that above only in that20 μL of sample was applied to each well in this case.

Probesets: FPL Name Function Sequence SEQ.I.D.NO: cynomolgousalpha-ENaC: cyENa001 CE cgccgtgggctgctgggTTTTTctcttggaaagaaagt 1683cyENa002 CE ggtaggagcggtggaactcTTTTTctcttggaaagaaagt 1684 cyENa003 CEcagaagaactcgaagagctctcTTTTTctcttggaaagaaagt 1685 cyENa004 CEcccagaaggccgtcttcatTTTTTctcttggaaagaaagt 1686 cyENa005 LEggtgcagagccagagcactgTTTTTctcttggaaagaaagt 1687 cyENa006 LEgtgccgcaggttctgggTTTTTaggcataggacccgtgtct 1688 cyENa007 LEgatcagggcctcctcctcTTTTTaggcataggacccgtgtct 1689 cyENa008 LEccgtggatggtggtattgttgTTTTTaggcataggacccgtgtct 1690 cyENa009 LEgcggttgtgctgggagcTTTTTaggcataggacccgtgtct 1691 cyENa0010 LEttgccagtacatcatgccaaaTTTTTaggcataggacccgtgtct 1692 cyENa0011 BLacaccaggcggatggcg 1693 eGFP: EGFP001 CEggcacgggcagcttgcTTTTTctcttggaaagaaagt 1694 EGFP002 CEggtagcggctgaagcactgTTTTTctcttggaaagaaagt 1695 EGFP003 CEcctggacgtagccttcgggTTTTTctcttggaaagaaagt 1696 EGFP004 CEccttgaagaagatggtgcgctTTTTTctcttggaaagaaagt 1697 EGFP005 LEcgaacttcacctcggcgcTTTTTctcttggaaagaaagt 1698 EGFP006 LEccttcagctcgatgcggtTTTTTctcttggaaagaaagt 1699 EGFP007 LEgtcacgagggtgggccagTTTTTaggcataggacccgtgtct 1700 EGFP008 LEcacgccgtaggtcagggtgTTTTTaggcataggacccgtgtct 1701 EGFP009 LEgtgctgcttcatgtggtcggTTTTTaggcataggacccgtgtct 1702 EGFP0010 LEtcaccagggtgtcgccctTTTTTaggcataggacccgtgtct 1703 EGFP0011 BLcggtggtgcagatgaacttca 1704 EGFP0012 BL catggcggacttgaagaagtc 1705EGFP0013 BL cgtcctccttgaagtcgatgc 1706

Table 2C shows the alpha-ENaC expression in cynomologous species forsiRNA examples.

Example 3.4 Screening for Interferon-α Induction

To evaluate the ability of siRNA to stimulate interferon-α (IFNα)release, siRNA was incubated with freshly purified peripheral bloodmononuclear cells (PBMCs) in vitro for 24 hours. The siRNA was addedeither directly to PBMCs, or first complexed with a lipid transfectionagent (GenePorter 2 or Lipofectamine 2000 or DOTAP transfection agent)and subsequently incubated with PBMCs. As positive controls for IFNαinduction, unmodified control sequences DI_A_(—)2216 and DI_A_(—)5167were included.

DI_A_(—)2216: is a single-stranded antisense DNA molecule

(SEQ.I.D.NO:1707) 5′-dGsdGsdGdGdGdAdCdGdAdTdCdGdTdCdGsdGsdGsdGsdGsd G-3′

DI_A_(—)5167 is a cholesterol-conjugated siRNA

5′-GUCAUCACACUGAAUACCAAU-s- (SEQ.I.D.NO:xxxx) chol-3′ 3′-Cs A sCAGUAGUGUGACUUAUGGUUA-5′ (SEQ.I.D.NO:1708)

After 24 hours, the IFNα was measured by ELISA. The basal IFNα level wasdetermined for untreated cells and was always very close to a water-onlycontrol. The addition of transfection agent alone gave no or littleincrease of IFNα levels. Known stimulatory oligonucleotides were addedto cells, either directly or in the presence of transfectant, and theexpected increases of IFNα were observed. This setup allows to determinethe stimulation of IFNα inhuman PBMC by siRNA (or otheroligonucleotides).

Isolation of Human PBMCs: A concentrated fraction of leukocytes (buffycoat) was obtained from the Blood Bank Suhl, Institute for TransfusionMedicine, Germany. These cells were negative for a variety of pathogens,including HIV, HCV, and others. The buffy coat was diluted 1:1 with PBS,added to a tube containing Ficoll, and centrifuged for 20 minutes at2200 rpm to allow fractionation. This was followed by removal of theturbid layer of white blood cells and transferred to a tube with freshPBS and Ficoll, which was centrifuged for 15 minutes at 2200 rpm. Theturbid layer of white blood cells was again removed, transferred to RPMI1640 culture medium and centrifuged for 5 minutes at 1,200 rpm to pelletthe white blood cells. The cells were resuspended in RPMI, pelleted asabove, and resuspended in media with 10% FCS to 1×10⁶/mL.

Interferon-αMeasurement: Cells in culture were combined with either 500nM (or 1 μM) oligonucleotide in Optimem or 133 nM oligonucleotide in GP2or Lipofectamine2000 or DOTAP transfection agent for 24 hours at 37° C.Interferon-α was measured with Bender Med Systems (Vienna, Austria)instant ELISA kit according to the manufacturer's instructions.

Selection of lead therapeutic sequences was based on a level of IFNαinduction of less than 15% of the positive control.

Example 3.5 Determination of siRNA Stability in Sputum of CF Patients

Sputum samples were collected by Dr. Ahmet Uluer, Children's HospitalBoston. After collection, sputum samples were treated with antibioticand were UV-irradiated to reduce bacterial content. To determine siRNAstability in sputum samples, siRNAs were incubated in 30 μL sputum at aconcentration of 5 μM at 37° C. for the indicated times. The reactionwas terminated by addition of proteinase K and samples were incubated at42° C. for another 20 minutes. A 40-mer RNA molecule made ofL-nucleotides (“Spiegelmer”) resistant to nuclease degradation was addedand served as calibration standard. Samples were filtered through a 0.2μm membrane to remove remaining debris. Samples were analyzed bydenaturing ion exchange HPLC on a DNAPac PA 200 column (Dionex) at pH11.0 using a gradient of sodium perchlorate for elution. siRNAs anddegradation products were quantified by determination of the area underthe peak for each sample. Concentration was normalized to theconcentration in the un-incubated samples.

The selection of the lead therapeutic sequences (ND8356, ND8357 andND8396) was based on an observed in vitro stability in CF sputum with ahalf-life greater than 60 minutes.

Example 3.6 Cross-Checking of Lead Therapeutic Sequences against KnownPolymorphisms in Human SCNN1A Gene

To exclude known polymorphisms from the target sites of lead candidates,lead siRNA sequences were checked against the NCBI single nucleotidepolymorphism (SNP) database(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=snp). Ofthe 10 known exon polymorphisms in the human SCNN1A gene, none wereshown to be present in the target sites of any of the 10 most potentlead therapeutic candidates.

Example 3.7 In Vitro Profiling of Top 5 Predicted Off-Target Sequences

A list of alignments for each sequence was sorted by homology over the19-mer region. Off-targets were scored based on the number and positionof the mismatches in accordance with the criteria described inexample 1. The top 5 off-target sequences were identified for each leadtherapeutic sequences (ND8356, ND8357 and ND8396). On- and off-targetsequences were individually cloned into a dual luciferase reportersystem (FIG. 2). Each cloned fragment encompassed the target 19nucleotides in addition to 10 nucleotides flanking region, both 5′ and3′ of the target sequence. The fragments were cloned into a multiplecloning site 3′ to the Renilla luciferase sequence, under the control ofan SV40 promoter. The activity of each siRNA against both on- andoff-target sequences was determined by the relative fluorescence of thetarget Renilla luciferase to the Firefly luciferase, the latter beingindependently controlled by the HSV-TK promoter. Initially,transfections were performed in COS-7 cells at an siRNA concentration of50 nM. Luciferase readouts were taken at 24 h post-transfection. At thishigh concentration of siRNA, no knockdown of greater than 30% wasobserved against any off-target sequence for any of the three leadsiRNAs. Activity against the on-target sequence was demonstrated with arelative reduction in Renilla luciferase activity of approximately 80%.IC50 curves were also generated for each siRNA against the on-targetsequence and controlled with the off-target sequences identified above.For each lead siRNA, on-target IC50's in this reporter assay were ofsimilar order of magnitude (10-50 pM) to the IC50's obtained against theendogenous target in H441 (Example 3.3) indicating that for ND8356,ND8357 and ND8396, potency against the on-target sequence was at least1000-5000 fold higher than for any of the predicted off-targetsequences.

Example 3.8 Genotoxicity Profiling

Cytotoxicity determination: Cytotoxicity was determined by using a cellcounter for the assessment of culture cell number.

It is well known that testing cytotoxic concentrations in vitro mayinduce genotoxic effects such as micronucleus formation. Therefore, weconsidered increased numbers of cells containing micronuclei appearingat cell counts of around 50% or less (compared to the concurrentnegative control) to be cytotoxicity-related if no dose-dependentincrease in micronucleated cells could already be observed atconcentrations showing moderate toxicity at most. The analysis of aconcentration showing at least 50% reduction in cell count is requiredby the guidelines regulating in vitro mammalian cell assays (OECD andICH guidelines for the conduction of chromosome aberration testing). Inaddition, OECD protocols require testing of non-toxic compounds toinclude at least one precipitating concentration (as long as thisdoesn't exceed 10 mM or 5 mg/ml, whichever is lower). Since the in vitromicronucleus test aims to predict the outcome of the regulatory assays,i.e. in vitro chromosomal aberration test, the protocol for the in vitromicronucleus test was designed to meet the requirements for these tests.

Test system: TK6 cells are Ebstein-Barr-Virus transfected andimmortalized cells (human lymphoblastoid origin derived from thespleen). Determination of the clastogenic and or aneugenic potential inthe micronucleus test in vitro with TK6 cells with/without S9-liverhomogenate (2%) from male rats (Aroclor 1254-pretreated). Treatmenttime: 20 hr (−S9), 3 hr (+S9). Sampling time: 24 hr after the start of3-hour treatment, 48 hr after the start of 20-hour treatment. For eachsubstance at least three concentrations (2 cultures per concentration)and 2000 cells per concentration were analyzed.

The micronucleus inducing effect for a tested concentration wasconsidered positive if the frequency of micronucleated cells was

>=2% and showed at least a doubling of the concurrent solvent controlvalue, OR

<2% and showed at least a 3-fold increase over the concurrent solventcontrol value

To conclude an experiment to be positive, dose-effect relationship andcytotoxicity have to be taken into account.

Summary: Lead therapeutic sequences ND8396, ND8356, ND8357 neitherinduced increased numbers of cells containing micronuclei after 20-hourtreatment without metabolic activation, nor after 3-hour treatment withor without S9. No cytotoxic concentration could be analyzed up to thetesting limit of 5 mg/ml.

Example 3.9 In Vitro Functional Efficacy in H441: ND8396

In order to demonstrate in vitro functional efficacy of lead siRNAagainst alphaENaC H441 cells were transfected with siRNA and preparedfor Ussings chamber analysis of ion transport. For transfection, H441cells were plated into T25 flasks at 2×10⁶ cells per flask in culturemedium supplemented with 200 nM Dexamethasone. Cells in each flask weretransfected with either ND8396 or a non targeting control siRNA at 30 nMsiRNA and 4 mL/mL Lipofectamine 2000 in a total volume of 5 mL (serumfree medium). One day after transfection, cells were plated onto 1 cm²Snapwell inserts at confluency (2×10⁵ cells per insert) to minimise thetime required for differentiation and formation of tight junctions andsupplied with medium in both the apical and the basolateral chambers.After one additional day of culture the apical medium was removed andthe basolateral medium replaced, thus taking the cells to air-liquidinterface (ALI) culture. Cells were maintained at ALI for a further sixdays prior to ion transport analysis.

For functional analysis in Ussings chambers, the Snapwell inserts weremounted in Vertical Diffusion Chambers (Costar) and were bathed withcontinuously gassed Ringer solution (5% CO₂ in %; pH 7.4) maintained at37° C. containing: 120 mM NaCl, 25 mM NaHCO₃, 3.3 mM KH₂PO₄, 0.8 mMK₂HPO₄, 1.2 mM CaCl₂, 1.2 mM MgCl₂, and 10 mM glucose. The solutionosmolarity was determined within the range of 280 and 300 mosmol kgH₂O.Cells were voltage clamped to 0 mV (model EVC4000; WPI). Transepithelialresistance (R_(T)) was measured by applying a 1 or 2-mV pulse at 30-sintervals, or using the initial potential difference across the cellsand the initial current measured, and then calculating R_(T) by Ohm'slaw. Data were recorded using a PowerLab workstation (ADInstruments).Following siRNA treatment the basal characteristics of the cells and theamiloride-sensitive short circuit current (I_(SC) following applicationof 10 μM amiloride; apical side only) were recorded. ENaC channelactivity in each culture was determined by the amiloride-sensitiveI_(SC) in each case.

Following assay, cells on the individual inserts were lysed for RNAanalysis. A knockdown of 75% at the RNA level at the time of assay(ND8396 as compared to non-targeting control) was correlated with afunctional knockdown of the amiloride sensitive current of approximately30% (ND8396 as compared to non-targeting control).

Nucleic acid sequences are represented below using standardnomenclature, and specifically the abbreviations of Table A.

TABLE A Abbreviations of nucleotide monomers used in nucleic acidsequence representation. It will be understood that these monomers, whenpresent in an oligonucleotide, are mutually linked by5′-3′-phosphodiester bonds. Abbreviation^(a) Nucleotide(s) Aadenosine-5′-phosphate C cytidine-5′-phosphate G guanosine-5′-phosphateT 2′-deoxy-thymidine-5′-phosphate U uridine-5′-phosphate c2′-O-methylcytidine-5′-phosphate u 2′-O-methyluridine-5′-phosphate Ts2′-deoxy-thymidine-5′-phosphorothioate

Table 1A: Selected siRNAs in initial screening set (human-rhesus ENaCalpha cross-reactive siRNAs). A total of 152 iRNA sequences wereidentified as an initial screening set, both with (sequence strands1-304) and without (sequence strands 305-608) backbone modification.iRNA sequences were designed to be fully complementary to both the humanand rhesus monkey alpha-ENaC sequences, according to the design criteriadescribed in the examples section. The percentage residual expression ofalpha-ENaC in two independent single-dose transfection experiments isshown (refer to examples section for methods used).

TABLE 1A 1st screen single dose @ 50 2nd screen nM in @ 50 nM in DuplexIC Seq ID Sense Seq ID Antisense H441; MV SD H441 SD ND8285   1AGcccGuAGcGuGGccuccTsT   2 GGAGGCcACGCuACGGGCUTsT 92% 4% 114% 15% ND8286   3 ccGGGuAAuGGuGcAcGGGTsT   4 CCCGUGcACcAUuACCCGGTsT 92% 4%114%  15%  ND8287   5 AuGcuAucGcGAcAGAAcATsT   6 UGUUCUGUCGCGAuAGcAUTsT27% 2% 35% 3% ND8288   7 uGcuAucGcGAcAGAAcAATsT   8UUGUUCUGUCGCGAuAGcATsT 23% 1% 32% 4% ND8289   9 GcccGuuuAuGuAuGcuccTsT 10 GGAGcAuAcAuAAACGGGCTsT 64% 2% 93% 5% ND8290  11GcccGuAGcGuGGccuccATsT  12 UGGAGGCcACGCuACGGGCTsT 83% 2% 115%  5% ND8291 13 ccGGAAAuuAAAGAGGAGcTsT  14 GCUCCUCUUuAAUUUCCGGTsT 54% 2% 79% 10% ND8292  15 ccGAAGGuuccGAAGccGATsT  16 UCGGCUUCGGAACCUUCGGTsT 40% 1% 54%8% ND8293  17 GcAAuucGGccuGcuuuucTsT  18 GAAAAGcAGGCCGAAUUGCTsT 41% 2%51% 4% ND8294  19 GGcGAAuuAcucucAcuucTsT  20 GAAGUGAGAGuAAUUCGCCTsT 19%1% 25% 5% ND8295  21 GcGAAuuAcucucAcuuccTsT  22 GGAAGUGAGAGuAAUUCGCTsT19% 5% 20% 1% ND8296  23 AAccAGGcGAAuuAcucucTsT  24GAGAGuAAUUCGCCUGGUUTsT 92% 4% 115%  19%  ND8297  25GGuAAuGGuGcAcGGGcAGTsT  26 CUGCCCGUGcACcAUuACCTsT 79% 2% 104%  14% ND8298  27 cucAcGAuGGcccucGGuGTsT  28 cACCGAGGGCcAUCGUGAGTsT 61% 3% 97%14%  ND8299  29 GcuccGAAGGuuccGAAGcTsT  30 GCUUCGGAACCUUCGGAGCTsT 16% 2%19% 3% ND8300  31 GccGAuAcuGGucuccAGGTsT  32 CCUGGAGACcAGuAUCGGCTsT 50%5% 55% 5% ND8301  33 ccGAuAcuGGucuccAGGcTsT  34 GCCUGGAGACcAGuAUCGGTsT53% 2% 65% 6% ND8302  35 uGcuGuuGcAccAuAcuuuTsT  36AAAGuAUGGUGcAAcAGcATsT 19% 1% 25% 3% ND8303  37 AAcGGucuGucccuGAuGcTsT 38 GcAUcAGGGAcAGACCGUUTsT 90% 3% 96% 11%  ND8304  39uuAAcuuGcGGccuGGcGuTsT  40 ACGCcAGGCCGcAAGUuAATsT 97% 3% 101%  11% ND8305  41 GcuGGuuAcucAcGAuGGcTsT  42 GCcAUCGUGAGuAACcAGCTsT 73% 2% 78%7% ND8306  43 uuAcucAcGAuGGcccucGTsT  44 CGAGGGCcAUCGUGAGuAATsT 91% 7%93% 6% ND8307  45 GAAGuuGAuAcuGGucuccTsT  46 GGAGACcAGuAUCGGCUUCTsT 71%3% 73% 6% ND8308  47 GAuAcuGGucuccAGGccGTsT  48 CGGCCUGGAGACcAGuAUCTsT86% 1% 90% 9% ND8309  49 AuAcuGGucuccAGGccGATsT  50UCGGCCUGGAGACcAGuAUTsT 71% 5% 70% 8% ND8310  51 cAAcGGucuGucccuGAuGTsT 52 cAUcAGGGAcAGACCGUUGTsT 80% 2% 84% 9% ND8311  53uuuAAcuuGcGGccuGGcGTsT  54 CGCcAGGCCGcAAGUuAAATsT 95% 2% 107%  15% ND8312  55 uAcucAcGAuGGcccucGGTsT  56 CCGAGGGCcAUCGUGAGuATsT 44% 2% 97%9% ND8313  57 uuucGGAGAGuAcuucAGcTsT  58 GCUGAAGuACUCUCCGAAATsT 14% 2%16% 2% ND8314  59 GcAGAcGcucuuuGAccuGTsT  60 cAGGUcAAAGAGCGUCUGCTsT 55%4% 58% 5% ND8315  61 cuAcAucuucuAuccGcGGTsT  62 CCGCGGAuAGAAGAUGuAGTsT20% 3% 26% 4% ND8316  63 AGGcGAAuuAcucucAcuuTsT  64AAGUGAGAGuAAUUCGCCUTsT 24% 1% 25% 2% ND8317  65 ccGcuucAAccAGGucuccTsT 66 GGAGACCUGGUUGAAGCGGTsT 62% 5% 64% 4% ND8318  67cAAccGcAuGAAGAcGGccTsT  68 GGCCGUCUUcAUGCGGUUGTsT 54% 6% 54% 4% ND8319 69 AuGAAGAcGGccuucuGGGTsT  69 CCcAGAAGGCCGUCUUcAUTsT 44% 4% 44% 6%ND8320  71 AGcAcAAccGcAuGAAGAcTsT  72 GUCUUcAUGCGGUUGUGCUTsT 15% 1% 16%1% ND8321  73 ucGAGuuccAccGcuccuATsT  74 uAGGAGCGGUGGAACUCGATsT 85% 5%89% 13%  ND8322  75 cuGcuucuAccAGAcAuAcTsT  76 GuAUGUCUGGuAGAAGcAGTsT46% 4% 44% 3% ND8323  77 GAGGGAGuGGuAccGcuucTsT  78GAAGCGGuACcACUCCCUCTsT 60% 7% 56% 3% ND8324  79 ccuuuAuGGAuGAuGGuGGTsT 80 CcACcAUcAUCcAuAAAGGTsT 83% 9% 82% 1% ND8325  81uGAGGGAGuGGuAccGcuuTsT  82 AAGCGGuACcACUCCCUcATsT 77% 6% 72% 2% ND8326 83 ccuGcAAccAGGcGAAuuATsT  84 uAAUUCGCCUGGUUGcAGGTsT 41% 4% 44% 7%ND8327  85 GGccuGGcGuGGAGAccucTsT  86 GAGGUCUCcACGCcAGGCCTsT 101%  5%95% 4% ND8328  87 uGcuuuucGGAGAGuAcuuTsT  88 AAGuACUCUCCGAAAAGcATsT 36%1% 51% 2% ND8329  89 cccGuAGcGuGGccuccAGTsT  90 CUGGAGGCcACGCuACGGGTsT52% 1% 51% 2% ND8330  91 ccGuAGcGuGGccuccAGcTsT  92GCUGGAGGCcACGCuACGGTsT 86% 9% 84% 3% ND8331  93 ccAGGcGAAuuAcucucAcTsT 94 GUGAGAGuAAUUCGCCUGGTsT 15% 2% 13% 1% ND8332  95GAAAcuGcuAuAcuuucAATsT  96 UUGAAAGuAuAGcAGUUUCTsT 10% 1% 10% 1% ND8333 97 GcccGGGuAAuGGuGcAcGTST  98 CGUGcACcAUuACCCGGGCTsT 83% 6% 82% 4%ND8334  99 cccGGGuAAuGGuGcAcGGTsT 100 CCGUGcACcAUuACCCGGGTsT 56% 4% 71%10%  ND8335 101 cGGGuAAuGGuGcAcGGGcTsT 102 GCCCGUGcACcAUuACCCGTsT 42% 3%91% 8% ND8336 103 GGGuAAuGGuGcAcGGGcATsT 104 UGCCCGUGcACcAUuACCCTsT 65%5% 71% 7% ND8337 105 uAAuGGuGcAcGGGcAGGATsT 106 UCCUGCCCGUGcACcAUuATsT46% 3% 46% 4% ND8338 107 cuGGuuAcucAcGAuGGccTsT 108GGCcAUCGUGAGuAACcAGTsT 74% 5% 79% 10%  ND8339 109 GuuAcucAcGAuGGcccucTsT110 GAGGGCcAUCGUGAGuAACTsT 85% 6% 92% 8% ND8340 111uGucAcGAuGGucAcccucTsT 112 GAGGGUGACcAUCGUGAcATsT 85% 4% 74% 5% ND8341113 uGcuccGAAGGuuccGAAGTsT 114 CUUCGGAACCUUCGGAGcATsT 37% 2% 32% 3%ND8342 115 uccGAAGGuuccGAAGccGTsT 116 CGGCUUCGGAACCUUCGGATsT 60% 4% 47%5% ND8343 117 uuccGAAGccGAuAcuGGuTsT 118 ACcAGuAUCGGCUUCGGAATsT 15% 1%13% 2% ND8344 119 AGccGAuAcuGGucuccAGTsT 120 CUGGAGACcAGuAUCGGCUTsT 49%3% 41% 3% ND8345 121 cuuGGuAcuGccucuGAAcTsT 122 GUUcAGAGGcAGuACcAAGTsT55% 2% 47% 4% ND8346 123 cucccGuAGcAcAcuAuAATsT 124UuAuAGUGUGCuACGGGAGTsT 67% 3% 57% 5% ND8347 125 ucccGuAGcAcAcuAuAAcTsT126 GUuAuAGUGUGCuACGGGATsT 29% 1% 26% 3% ND8348 127uGcAccAuAcuuucuuGuATsT 128 uAcAAGAAAGuAUGGUGcATsT 17% 1% 15% 3% ND8349129 uuGcccGuuuAuGuAuGcuTsT 130 AGcAuAcAuAAACGGGcAATsT 68% 2% 50% 4%ND8350 131 uGcccGuuuAuGuAuGcucTsT 132 GAGcAuAcAuAAACGGGcATsT 59% 8% 44%6% ND8351 133 GGAcccuAGAccucuGcAGTsT 134 CUGcAGAGGUCuAGGGUCCTsT 86% 11% 82% 2% ND8352 135 ccuAGAccucuGcAGcccATsT 136 UGGGCUGcAGAGGUCuAGGTsT 69%7% 79% 3% ND8353 137 uGGcAuGAuGuAcuGGcAATsT 138 UUGCcAGuAcAUcAUGCcATsT58% 4% 52% 4% ND8354 139 uAcuGGcAAuucGGccuGcTsT 140GcAGGCCGAAUUGCcAGuATsT 101%  4% 100%  4 ND8355 141AAuucGGccuGcuuuucGGTsT 142 CCGAAAAGcAGGCCGAAUUTsT 49% 1% 43% 6% ND8356143 cuGcuuuucGGAGAGuAcuTsT 144 AGuACUCUCCGAAAAGcAGTsT 17% 3% 18% 1%ND8357 145 uucGGAGAGuAcuucAGcuTsT 146 AGCUGAAGuACUCUCCGAATsT 13% 3% 16%2% ND8358 147 AGcAGAcGcucuuuGAccuTsT 148 AGGUcAAAGAGCGUCUGCUTsT 73% 9%71% 5% ND8359 149 cuuGcAGcGccuGAGGGucTsT 150 GACCCUcAGGCGCUGcAAGTsT 57%9% 64% 7% ND8360 151 uGGcuuuAAcuuGcGGccuTsT 152 AGGCCGcAAGUuAAAGCcATsT102%  5% 82% 8% ND8361 153 GcuuuAAcuuGcGGccuGGTsT 154CcAGGCCGcAAGUuAAAGCTsT 83% 5% 82% 8% ND8362 155 uAAcuuGcGGccuGGcGuGTsT156 cACGCcAGGCCGcAAGUuATsT 119%  3% 13% 2% ND8363 157AccuuuAcccuucAAAGuATsT 158 uACUUUGAAGGGuAAAGGUTsT 17% 3% 13% 2% ND8364159 GGuuAcucAcGAuGGcccuTsT 160 AGGGCcAUCGUGAGuAACCTsT 104%  9% 117% 17%  ND8365 161 cAcGAuGGcccucGGuGAcTsT 162 GUcACCGAGGGCcAUCGUGTsT 140% 13%  100%  9% ND8366 163 AGAuGcuAucGcGAcAGAATsT 164UUCUGUCGCGAuAGcAUCUTsT 46% 2% 70% 6% ND8367 165 AcGAuGGucAcccuccuGuTsT166 AcAGGAGGGUGACcAUCGUTsT 85% 6% 128%  10%  ND8368 167cuccGAAGGuuccGAAGccTsT 168 GGCUUCGGAACCUUCGGAGTsT 12% 2% 18% 1% ND8369169 AAGGuuccGAAGccGAuAcTsT 170 GuAUCGGCUUCGGAACCUUTsT 63% 7% 114%  19% ND8370 171 GGuAcuGccucuGAAcAcuTsT 172 AGUGUUcAGAGGcAGuACCTsT 36% 1% 21%1% ND8371 173 AGcuuuGAcAAGGAAcuuuTsT 174 AAAGUUCCUUGUcAAAGCUTsT 17% 1%21% 1% ND8372 175 uuuGAcAAGGAAcuuuccuTsT 176 AGGAAAGUUCCUUGUcAAATsT 16%2% 26% 4% ND8373 177 uGAcAAGGAAcuuuccuAATsT 178 UuAGGAAAGUUCCUUGUcATsT12% 1% 22% 5% ND8374 179 cccGuAGcAcAcuAuAAcATsT 180UGUuAuAGUGUGCuACGGGTsT 41% 2% 75% 3% ND8375 181 cAcuAuAAcAucuGcuGGATsT182 UCcAGcAGAUGUuAuAGUGTsT 17% 1% 26% 2% ND8376 183uuGcuGuuGcAccAuAcuuTsT 184 AAGuAUGGUGcAAcAGcAATsT 45% 4% 69% 6% ND8377185 GuAcuGGcAAuucGGccuGTsT 186 cAGGCCGAAUUGCcAGuACTsT 60% 6% 120%  8%ND8378 187 uucGGccuGcuuuucGGAGTsT 188 CUCCGAAAAGcAGGCCGAATsT 57% 5% 86%11%  ND8379 189 ccuGcuuuucGGAGAGuAcTsT 190 GuACUCUCCGAAAAGcAGGTsT 43% 5%50% 3% ND8380 191 GcuuuucGGAGAGuAcuucTsT 192 GAAGuACUCUCCGAAAAGCTsT 16%2% 24% 2% ND8381 193 cuuuucGGAGAGuAcuucATsT 194 UGAAGuACUCUCCGAAAAGTsT12% 1% 16% 3% ND8382 195 cAAccucAAcucGGAcAAGTsT 196CUUGUCCGAGUUGAGGUUGTsT 33% 2% 39% 3% ND8383 197 cuAccAGAcAuAcucAucATsT198 UGAUGAGuAUGUCUGGuAGTsT 13% 1% 23% 6% ND8384 199cuGucGAGGcuGccAGAGATsT 200 UCUCUGGcAGCCUCGAcAGTsT 11% 1% 18% 3% ND8385201 AAAcuGcuAuAcuuucAAuTsT 202 AUUGAAAGuAuAGcAGUUUTsT 48% 8% 64% 11% ND8386 203 GGcuuuAAcuuGcGGccuGTsT 204 cAGGCCGcAAGUuAAAGCCTsT 55% 7% 70%8% ND8387 205 cuuuAAcuuGcGGccuGGcTsT 206 GCcAGGCCGcAAGUuAAAGTsT 40% 11% 87% 14%  ND8388 207 AGGuGuGuAuucAcuccuGTsT 208 cAGGAGUGAAuAcAcACCUTsT45% 3% 41% 5% ND8389 209 AcGAuGGcccucGGuGAcATsT 210UGUcACCGAGGGCcAUCGUTsT 43% 2% 60% 9% ND8390 211 cuGAAcAcucuGGuuucccTsT212 GGGAAACuAGAGUGUUcAGTsT 33% 2% 48% 11%  ND8391 213cuAuAAcAucuGcuGGAGuTsT 214 ACUCcAGcAGAUGUuAuAGTsT 16% 1% 17% 4% ND8392215 GcAccAuAcuuucuuGuAcTsT 216 GuAcAAGAAAGuAUGGUGCTsT 19% 1% 22% 4%ND8393 217 uGucuAGcccAucAuccuGTsT 218 cAGGAUGAUGGGCuAGAcATsT 69% 3% 92%15%  ND8394 219 AGGAcccuAGAccucuGcATsT 220 UGcAGAGGUCuAGGGUCCUTsT 94% 5%86% 13%  ND8395 221 ccAccGcuccuAccGAGAGTsT 222 CUCUCGGuAGGAGCGGUGGTsT55% 1% 65% 6% ND8396 223 uAccGAGAGcucuucGAGuTsT 224ACUCGAAGAGCUCUCGGuATsT 11% 1% 11% 1% ND8397 225 AAcAuccuGucGAGGcuGcTsT226 GcAGCCUCGAcAGGAUGUUTsT 90% 7% 72% 11%  ND8398 227GAAccuuuAcccuucAAAGTsT 228 CUUUGAAGGGuAAAGGUUCTsT 22% 2% 25% 4% ND8399229 GGuuccGAAGccGAuAcuGTsT 230 cAGuAUCGGCUUCGGAACCTsT 93% 9% 89% 9%ND8400 231 AAGccGAuAcuGGucuccATsT 232 UGGAGACcAGuAUCGGCUUTsT 35% 2% 42%9% ND8401 233 ucuAGcccAucAuccuGcuTsT 234 AGcAGGAUGAUGGGCuAGATsT 95% 8%95% 14%  ND8402 235 cGGcGccAuccGccuGGuGTsT 236 cACcAGGCGGAUGGCGCCGTsT81% 8% 89% 17%  ND8403 237 uuuucGGAGAGuAcuucAGTsT 238CUGAAGuACUCUCCGAAAATsT 13% 1% 13% 1% ND8404 239 GAGAGuAcuucAGcuAcccTsT240 GGGuAGCUGAAGuACUCUCTsT 71% 3% 100%  10%  ND8405 241GAcGcucuuuGAccuGuAcTsT 242 GuAcAGGUcAAAGAGCGUCTsT 84% 5% 92% 13%  ND8406243 uGuGuAuucAcuccuGcuuTsT 244 AAGuAGGAGUGAAuAcAcATsT 78% 2% 89% 8%ND8407 245 AAcAAcAAGAGAAAuGGAGTsT 246 CUCcAUUUCUCUUGUUGUUTsT 66% 3% 88%21%  ND8408 247 AuuGAAGGAuGuGcAGGGcTsT 248 GCCCUGcAcAUCCUUcAAUTsT 25% 1%36% 6% ND8409 249 ucucAGAGccGcccAAAcuTsT 250 AGUUUGGGCGGCUCUGAGATsT 18%1% 24% 2% ND8410 251 AAAcAcAAccAAGGGuAcATsT 252 UGuACCCUUGGUUGUGUUUTsT21% 1% 35% 2% ND8411 253 uAcccGuGcccucAcAGAGTsT 254CUCUGUGAGGGcACGGGuATsT 57% 2% 67% 4% ND8412 255 uAGcAcAcuAuAAcAucuGTsT256 cAGAUGUuAuAGUGUGCuATsT 30% 2% 41% 1% ND8413 257GGuGuGuAuucAcuccuGcTsT 258 GcAGGAGUGAAuAcAcACCTsT 73% 1% 90% 9% ND8414259 cAuGAucAAGGAGuGuGGcTsT 260 GCuAcACUCCUUGAUcAUGTsT 65% 2% 67% 5%ND8415 261 AcucAcGAuGGcccucGGuTsT 262 ACCGAGGGCcAUCGUGAGUTsT 96% 6% 95%6% ND8416 263 GGAGcuuuGAcAAGGAAcuTsT 264 AGUUCCUUGUcAAAGCUCCTsT 24% 1%28% 4% ND8417 265 AuAcccGuGcccucAcAGATsT 266 UCUGUGAGGGcACGGGuAUTsT 54%1% 62% 2% ND8418 267 GGAGuGGccAAAGucAAcATsT 268 UGUUGACUUUGGCcACUCCTsT93% 2% 86% 11%  ND8419 269 AAcuAcAAAAccAAuucuGTsT 270cAGAAUUGGUUUUGuAGUUTsT 101%  5% 108%  19%  ND8420 271uGcuGGAGuGuuGcuGuuGTsT 272 cAAcAGcAAcACUCcAGcATsT 29% 1% 26% 1% ND8421273 AGGucuccuGcAAccAGGcTsT 274 GCCUGGUUGcAGGAGACCUTsT 95% 10%  91% 17% ND8422 275 cuuuGGcAuGAuGuAcuGGTsT 276 CcAGuAcAUcAUGCcAAAGTsT 86% 3% 84%6% ND8423 277 cAucuGcAcccucAAucccTsT 278 GGGAUUGAGGGUGcAGAUGTsT 82% 11% 73% 4% ND8424 279 cGAcuGcAccAAGAAuGGcTsT 280 GCcAUUCUUGGUGcAGUCGTsT 70%8% 69% 7% ND8425 281 AAAAcAcAAccAAGGGuAcTsT 282 GuACCCUUGGUUGUGUUUUTsT95% 6% 106%  12%  ND8426 283 cAucuGcuGGAGuGuuGcuTsT 284AGcAAcACUCcAGcAGAUGTsT 30% 2% 37% 1% ND8427 285 ccuAcAucuucuAuccGcGTsT286 CGCGGAuAGAAGAUGuAGGTsT 42% 6% 30% 1% ND8428 287GccuAcAucuucuAuccGcTsT 288 GCGGAuAGAAGAUGuAGGCTsT 65% 7% 54% 3% ND8429289 GAGuGGuAccGcuuccAcuTsT 290 AGUGGAAGCGGuACcACUCTsT 95% 11%  86% 19% ND8430 291 GGuAccGcuuccAcuAcAuTsT 292 AUGuAGUGGAAGCGGuACCTsT 111%  19% 96% 26%  ND8431 293 GuGGuAccGcuuccAcuAcTsT 294 GuAGUGGAAGCGGuACcACTsT98% 13%  52% 26%  ND8432 295 GAAuuAcucucAcuuccAcTsT 296GUGGAAGUGAGAGuAAUUCTsT 111%  21%  73% 27%  ND8433 297AAuuAcucucAcuuccAccTsT 298 GGUGGAAGUGAGAGuAAUUTsT 109%  22%  105%  7%ND8434 299 uAcucucAcuuccAccAccTsT 300 GGUGGUGGAAGUGAGAGuATsT 106%  23% 95% 7% ND8435 301 AGuGGuAccGcuuccAcuATsT 302 uAGUGGAAGCGGuACcACUTsT109%  18%  102%  9% ND8434 303 GGGcAAcuucAucuucGccTsT 304GGCGAAGAUGAAGUUGCCCTsT 109%  18%  107%  14%  ND-8501 305AGCCCGUAGCGUGGCCUCCTsT 306 GGAGGCCACGCUACGGGCUTsT 84% 14%  69% 3%ND-8502 307 CCGGGUAAUGGUGCACGGGTsT 208 CCCGUGCACCAUUACCCGGTsT 41% 6% 30%2% ND-8503 309 AUGCUAUCGCGACAGAACATsT 310 UGUUCUGUCGCGAUAGCAUTsT 11% 2%10% 2% ND-8504 311 UGCUAUCGCGACAGAACAATsT 312 UUGUUCUGUCGCGAUAGCATsT 1%2% 10% 0% ND-8505 313 GCCCGUUUAUGUAUGCUCCTsT 314 GGAGCAUACAUAAACGGGCTsT23% 3% 16% 1% ND-8506 315 GCCCGAUGCGUGGCCUCCATsT 316UGGAGGCCACGCUACGGGCTsT 32% 3% 22% 1% ND-8507 317 CCGGAAAUUAAAGAGGAGCTsT318 GCUCCUCUUUAAUUUCCGGTsT 35% 4% 24% 1% ND-8508 319CCGAAGGUUCCGAAGCCGATsT 320 UCGGCUUCGGAACCUUCGGTsT 19% 2% 13% 1% ND-8509321 GCAAUUCGGCCUGCUUUUCTsT 322 GAAAAGCAGGCCGAAUUGCTsT 12% 1% 8% 1%ND-8510 323 GGCGAAUUACUCUCACUUCTsT 324 GAAGUGAGAGUAAUUCGCCTsT 21% 2% 18%1% ND-8511 325 GCGAAUUACUCUCACUUCCTsT 326 GGAAGUGAGAGUAAUUCGCTsT 12% 2% 8% 1% ND-8512 327 AACCAGGCGAAUUACUCUCTsT 328 GAGAGUAAUUCGCCUGGUUTsT 99%11%  79% 5% ND-8513 329 GGUAAUGGUGCACGGGCAGTsT 330CUGCCCGUGCACCAUUACCTsT 61% 6% 42% 4% ND-8514 331 CUCACGAUGGCCCUCGGUGTsT332 CACCGAGGGCCAUCGUGAGTsT 94% 11%  70% 4% ND-8515 333GCUCCGAAGGUUCCGAAGCTsT 334 GCUUCGGAACCUUCGGAGCTsT 18% 2% 17% 2% ND-8516335 GCCGAUACUGGUCUCCAGGTsT 336 CCUGGAGACCAGUAUCGGCTsT 14% 1% 12% 1%ND-8517 337 CCGAUACUGGUCUCCAGGCTsT 338 GCCUGGAGACCAGUAUCGGTsT 42% 5% 33%2% ND-8518 339 UGCUGUUGCACCAUACUUUTsT 340 AAAGUAUGGUGCAACAGCATsT 10% 1% 9% 0% ND-8519 341 AACGGUCUGUCCCUGAUGCTsT 342 GCAUCAGGGACAGACCGUUTsT 60%7% 52% 8% ND-8520 343 UUAACUUGCGGCCUGGCGUTsT 344 ACGCCAGGCCGCAAGUUAATsT82% 25%  77% 18%  ND-8521 345 GCUGGUUACUCACGAUGGCTsT 346GCCAUCGUGAGUAACCAGCTsT 36% 4% 34% 7% ND-8522 347 UUACUCACGAUGGCCCUCGTsT348 CGAGGGCCAUCGUGAGUAATsT 105%  21%  113%  21%  ND-8523 349GAAGCCGAUACUGGUCUCCTsT 350 GGAGACCAGUAUCGGCUUCTsT 24% 2% 18% 2% ND-8524351 GAUACUGGUCUCCAGGCCGTsT 352 CGGCCUGGAGACCAGUAUCTsT 30% 5% 25% 3%ND-8525 353 AUACUGGUCUCCAGGCCGATsT 354 UCGGCCUGGAGACCAGUAUTsT 12% 1% 11%2% ND-8526 355 CAACGGUCUGUCCCUGAUGTsT 356 CAUCAGGGACAGACCGUUGTsT 24% 7%24% 2% ND-8527 357 UUUAACUUGCGGCCUGGCGTsT 358 CGCCAGGCCGCAAGUUAAATsT122%  6% 107%  9% ND-8528 359 UACUCACGAUGGCCCUCGGTsT 360CCGAGGGCCAUCGUGAGUATsT 78% 6% 84% 7% ND-8529 361 UUUCGGAGAGUACUUCAGCTsT362 GCUGAAGUACUCUCCGAAATsT 87% 18%  80% 17%  ND-8530 363GCAGACGCUCUUUGACCUGTsT 364 CAGGUCAAAGAGCGUCUGCTsT 14% 2% 13% 0% ND-8531365 CUACAUCUUCUAUCCGCGGTsT 366 CCGCGGAUAGAAGAUGUAGTsT 20% 4% 18% 3%ND-8532 367 AGGCGAAUUACUCUCACUUTsT 368 AAGUGAGAGUAAUUCGCCUTsT 25% 5% 18%1% ND-8533 369 CCGCUUCAACCAGGUCUCCTsT 370 GGAGACCUGGUUGAAGCGGTsT 30%11%  22% 2% ND-8534 371 CAACCGCAUGAAGACGGCCTsT 372GGCCGUCUUCAUGCGGUUGTsT 33% 4% 23% 1% ND-8535 373 AUGAAGACGGCCUUCUGGGTsT374 CCCAGAAGGCCGUCUUCAUTsT 114%  12%  84% 15%  ND-8536 375AGCACAACCGCAUGAAGACTsT 376 GUCUUCAUGCGGUUGUGCUTsT 18% 1% 16% 3% ND-8537377 UCGAGUUCCACCGCUCCUATsT 378 UAGGAGCGGUGGAACUCGATsT 25% 0% 26% 3%ND-8538 379 CUGCUUCUACCAGACAUACTsT 380 GUAUGUCUGGUAGAAGCAGTsT 12% 1% 13%2% ND-8539 381 GAGGGAGUGGUACCGCUUCTsT 382 GAAGCGGUACCACUCCCUCTsT 43% 1%47% 14%  ND-8540 383 CCUUUAUGGAUGAUGGUGGTsT 384 CCACCAUCAUCCAUAAAGGTsT61% 5% 60% 8% ND-8541 385 UGAGGGAGUGGUACCGCUUTsT 386AAGCGGUACCACUCCCUCATsT 36% 5% 35% 5% ND-8542 387 CCUGCAACCAGGCGAAUUATsT388 UAAUUCGCCUGGUUGCAGGTsT 19% 2% 16% 1% ND-8543 389GGCCUGGCGUGGAGACCUCTsT 390 GAGGUCUCCACGCCAGGCCTsT 28% 7% 20% 2% ND-8544391 UGCUUUUCGGAGAGUACUUTsT 392 AAGUACUCUCCGAAAAGCATsT 22% 5% 17% 1%ND-8545 393 CCCGUAGCGUGGCCUCCAGTsT 394 CUGGAGGCCACGCUACGGGTsT 25% 3% 22%2% ND-8546 395 CCGUAGCGUGGCCUCCAGCTsT 396 GCUGGAGGCCACGCUACGGTsT 62% 5%57% 9% ND-8547 397 CCAGGCGAAUUACUCUCACTsT 398 GUGAGAGUAAUUCGCCUGGTsT 23%11%  16% 2% ND-8548 399 GAAACUGCUAUACUUUCAATsT 400UUGAAAGUAUAGCAGUUUCTsT  9% 3%  3% 0% ND-8549 401 GCCCGGGUAAUGGUGCACGTsT402 CGUGCACCAUUACCCGGGCTsT 87% 9% 92% 14%  ND-8550 403CCCGGGUAAUGGUGCACGGTsT 404 CCGUGCACCAUUACCCGGGTsT 19% 12%  14% 1%ND-8551 405 CGGGUAAUGGUGCACGGGCTsT 406 GCCCGUGCACCAUUACCCGTsT 68% 11% 73% 3% ND-8552 407 GGGUAAUGGUGCACGGGCATsT 408 UGCCCGUGCACCAUUACCCTsT 30%6% 33% 2% ND-8553 409 UAAUGGUGCACGGGCAGGATsT 410 UCCUGCCCGUGCACCAUUATsT29% 3% 31% 1% ND-8554 411 CUGGUUACUCACGAUGGCCTsT 412GGCCAUCGUGAGUAACCAGTsT 74% 15%  66% 8% ND-8555 413GUUACUCACGAUGGCCCUCTsT 414 GAGGGCCAUCGUGAGUAACTsT 91% 21%  88% 10% ND-8556 415 UGUCACGAUGGUCACCCUCTsT 416 GAGGGUGACCAUCGUGACATsT 72% 4% 76%12%  ND-8557 417 UGCUCCGAAGGUUCCGAAGTsT 418 CUUCGGAACCUUCGGAGCATsT 51%2% 59% 18%  ND-8558 419 UCCGAAGGUUCCGAAGCCGTsT 420CGGCUUCGGAACCUUCGGATsT 109%  11%  77% 13%  ND-8559 421UUCCGAAGCCGAUACUGGUTsT 422 ACCAGUAUCGGCUUCGGAATsT 46% 20%  33% 6%ND-8560 423 AGCCGAUACUGGUCUCCAGTsT 424 CUGGAGACCAGUAUCGGCUTsT 15% 6% 10%1% ND-8561 425 CUUGGUACUGCCUCUGAACTsT 426 GUUCAGAGGCAGUACCAAGTsT 16% 3%12% 3% ND-8562 427 CUCCCGUAGCACACUAUAATsT 428 UUAUAGUGUGCUACGGGAGTsT 14%6% 10% 1% ND-8563 429 UCCCGUAGCACACUAUAACTsT 430 GUUAUAGUGUGCUACGGGATsT43% 11%  36% 4% ND-8564 431 UGCACCAUACUUUCUUGUATsT 432UACAAGAAAGUAUGGUGCATsT 17% 6% 13%  3% ND-8565 433 UUGCCCGUUUAUGUAUGCUTsT434 AGCAUACAUAAACGGGCAATsT 84% 2% 103%  12%  ND-8566 435UGCCCGUUUAUGUAUGCUCTsT 436 GAGCAUACAUAAACGGGCATsT 69% 25%  93% 4%ND-8567 437 GGACCCUAGACCUCUGCAGTsT 438 CUGCAGAGGUCUAGGGUCCTsT 29% 8% 33%2% ND-8568 439 CCUAGACCUCUGCAGCCCATsT 440 UGGGCUGCAGAGGUCUAGGTsT 18% 2%19% 1% ND-8569 441 UGGCAUGAUGUACUGGCAATsT 442 UUGCCAGUACAUCAUGCCATsT 19%3% 20% 5% ND-8570 443 UACUGGCAAUUCGGCCUGCTsT 444 GCAGGCCGAAUUGCCAGUATsT86% 15%  83% 16%  ND-8571 445 AAUUCGGCCUGCUUUUCGGTsT 446CCGAAAAGCAGGCCGAAUUTsT 19% 3% 24% 4% ND-8572 447 CUGCUUUUCGGAGAGUACUTsT448 AGUACUCUCCGAAAAGCAGTsT  8% 2% 40% 2% ND-8573 449UUCGGAGAGUACUUCAGCUTsT 450 AGCUGAAGUACUCUCCGAATsT 27% 3% 40% 5% ND-8574451 AGCAGACGCUCUUUGACCUTsT 452 AGGUCAAAGAGCGUCUGCUTsT 15% 0% 19% 4%ND-8575 453 CUUGCAGCGCCUGAGGGUCTsT 454 GACCCUCAGGCGCUGCAAGTsT 35% 1% 40%4% ND-8576 455 UGGCUUUAACUUGCGGCCUTsT 456 AGGCCGCAAGUUAAAGCCATsT 7% 3%53% 8% ND-8577 457 GCUUUAACUUGCGGCCUGGTsT 458 CCAGGCCGCAAGUUAAAGCTsT 20%2% 25% 5% ND-8578 459 UAACUUGCGGCCUGGCGUGTsT 460 CACGCCAGGCCGCAAGUUATsT75% 7% 82% 4% ND-8579 461 ACCUUUACCCUUCAAAGUATsT 462UACUUUGAAGGGUAAAGGUTsT 14% 2% 17% 3% ND-8580 463 GGUUACUCACGAUGGCCCUTsT464 AGGGCCAUCGUGAGUAACCTsT 63% 5% 70% 11%  ND-8581 465CACGAUGGCCCUCGGUGACTsT 466 GUCACCGAGGGCCAUCGUGTsT 56% 2% 50% 5% ND-8582467 AGAUGCUAUCGCGACAGAATsT 468 UUCUGUCGCGAUAGCAUCUTsT 18% 1% 18% 1%ND-8583 469 ACGAUGGUCACCCUCCUGUTsT 470 ACAGGAGGGUGACCAUCGUTsT 48% 3% 52%6% ND-8584 471 CUCCGAAGGUUCCGAAGCCTsT 472 GGCUUCGGAACCUUCGGAGTsT 18% 2%20% 5% ND-8585 473 AAGGUUCCGAAGCCGAUACTsT 474 GUAUCGGCUUCGGAACCUUTsT 26%2% 28% 1% ND-8586 475 GGUACUGCCUCUGAACACUTsT 476 AGUGUUCAGAGGCAGUACCTsT12% 1% 12% 1% ND-8587 477 AGCUUUGACAAGGAACUUUTsT 478AAAGUUCCUUGUCAAAGCUTsT 17% 2% 18% 2% ND-8588 479 UUUGACAAGGAACUUUCCUTsT480 AGGAAAGUUCCUUGUCAAATsT 78% 5% 73% 2% ND-8589 481UGACAAGGAACUUUCCUAATsT 482 UUAGGAAAGUUCCUUGUCATsT 14% 1% 16% 1% ND-8590483 CCCGUAGCACACUAUAACATsT 484 UGUUAUAGUGUGCUACGGGTsT  9% 1% 11% 2%ND-8591 485 CACUAUAACAUCUGCUGGATsT 486 UCCAGCAGAUGUUAUAGUGTsT 18% 2% 20%2% ND-8592 487 UUGCUGUUGCACCAUACUUTsT 488 AAGUAUGGUGCAACAGCAATsT 23% 2%25% 8% ND-8593 489 GUACUGGCAAUUCGGCCUGTsT 490 CAGGCCGAAUUGCCAGUACTsT 66%3% 62% 4% ND-8594 491 UUCGGCCUGCUUUUCGGAGTsT 492 CUCCGAAAAGCAGGCCGAATsT97% 7% 86% 8% ND-8595 493 CCUGCUUUUCGGAGAGUACTsT 494GUACUCUCCGAAAAGCAGGTsT 11% 2% 14% 3% ND-8596 495 GCUUUUCGGAGAGUACUUCTsT496 GAAGUACUCUCCGAAAAGCTsT 12% 1% 17% 2% ND-8597 497CUUUUCGGAGAGUACUUCATsT 498 UGAAGUACUCUCCGAAAAGTsT 11% 1% 14% 2% ND-8598499 CAACCUCAACUCGGACAAGTsT 500 CUUGUCCGAGUUGAGGUUGTsT 15% 2% 16% 2%ND-8599 501 CUACCAGACAUACUCAUCATsT 502 UGAUGAGUAUGUCUGGUAGTsT 17% 1% 18%2% ND-8600 503 CUGUCGAGGCUGCCAGAGATsT 504 UCUCUGGCAGCCUCGACAGTsT 17% 0%16% 1% ND-8601 505 AAACUGCUAUACUUUCAAUTsT 506 AUUGAAAGUAUAGCAGUUUTsT 28%1% 26% 1% ND-8602 507 GGCUUUAACUUGCGGCCUGTsT 508 CAGGCCGCAAGUUAAAGCCTsT21% 2% 18% 1% ND-8603 509 CUUUAACUUGCGGCCUGGCTsT 510GCCAGGCCGCAAGUUAAAGTsT 81% 2% 69% 6% ND-8604 511 AGGUGUGUAUUCACUCCUGTsT512 CAGGAGUGAAUACACACCUTsT 47% 4% 40% 1% ND-8605 513ACGAUGGCCCUCGGUGACATsT 514 UGUCACCGAGGGCCAUCGUTsT 40% 6% 35% 2% ND-8606515 CUGAACACUCUGGUUUCCCTsT 516 GGGAAACCAGAGUGUUCAGTsT 60% 2% 75% 4%ND-8607 517 CUAUAACAUCUGCUGGAGUTsT 518 ACUCCAGCAGAUGUUAUAGTsT 17% 1% 24%3% ND-8608 519 GCACCAUACUUUCUUGUACTsT 520 GUACAAGAAAGUAUGGUGCTsT 10% 1%15% 3% ND-8609 521 UGUCUAGCCCAUCAUCCUGTsT 522 CAGGAUGAUGGGCUAGACATsT 62%2% 75% 12%  ND-8610 523 AGGACCCUAGACCUCUGCATsT 524UGCAGAGGUCUAGGGUCCUTsT 61% 5% 73% 10%  ND-8611 525CCACCGCUCCUACCGAGAGTsT 526 CUCUCGGUAGGAGCGGUGGTsT 21% 2% 29% 5% ND-8612527 UACCGAGAGCUCUUCGAGUTsT 528 ACUCGAAGAGCUCUCGGUATsT 13% 1% 22% 3%ND-8613 529 AACAUCCUGUCGAGGCUGCTsT 530 GCAGCCUCGACAGGAUGUUTsT 57% 2% 70%4% ND-8614 531 GAACCUUUACCCUUCAAAGTsT 532 CUUUGAAGGGUAAAGGUUCTsT 13% 3%16% 2% ND-8615 533 GGUUCCGAAGCCGAUACUGTsT 534 CAGUAUCGGCUUCGGAACCTsT 18%1% 24% 2% ND-8616 535 AAGCCGAUACUGGUCUCCATsT 536 UGGAGACCAGUAUCGGCUUTsT19% 1% 25% 2% ND-8617 537 UCUAGCCCAUCAUCCUGCUTsT 538AGCAGGAUGAUGGGCUAGATsT 93% 3% 101%  3% ND-8618 539CGGCGCCAUCCGCCUGGUGTsT 540 CACCAGGCGGAUGGCGCCGTsT 85% 4% 99% 4% ND-8619541 UUUUCGGAGAGUACUUCAGTsT 542 CUGAAGUACUCUCCGAAAATsT 63% 2% 77% 3%ND-8620 543 GAGAGUACUUCAGCUACCCTsT 544 GGGUAGCUGAAGUACUCUCTsT 26% 1% 30%4% ND-8621 545 GACGCUCUUUGACCUGUACTsT 546 GUACAGGUCAAAGAGCGUCTsT 17% 2%19% 3% ND-8622 547 UGUGUAUUCACUCCUGCUUTsT 548 AAGCAGGAGUGAAUACACATsT 49%3% 58% 11%  ND-8623 549 AACAACAAGAGAAAUGGAGTsT 550CUCCAUUUCUCUUGUUGUUTsT 74% 7% 70% 4% ND-8624 551 AUUGAAGGAUGUGCAGGGCTsT552 GCCCUGCACAUCCUUCAAUTsT 85% 6% 87% 12%  ND-8625 553UCUCAGAGCCGCCCAAACUTsT 554 AGUUUGGGCGGCUCUGAGATsT 53% 3% 51% 6% ND-8626555 AAACACAACCAAGGGUACATsT 556 UGUACCCUUGGUUGUGUUUTsT 17% 2% 18% 2%ND-8627 557 UACCCGUGCCCUCACAGAGTsT 558 CUCUGUGAGGGCACGGGUATsT 58% 3% 55%3% ND-8628 559 UAGCACACUAUAACAUCUGTsT 560 CAGAUGUUAUAGUGUGCUATsT 64% 3%64% 15%  ND-8629 561 GGUGUGUAUUCACUCCUGCTsT 562 GCAGGAGUGAAUACACACCTsT25% 3% 23% 2% ND-8630 563 CAUGAUCAAGGAGUGUGGCTsT 564GCCACACUCCUUGAUCAUGTsT 32% 2% 28% 2% ND-8631 565 ACUCACGAUGGCCCUCGGUTsT566 ACCGAGGGCCAUCGUGAGUTsT 96% 1% 88% 4% ND-8632 567GGAGCUUUGACAAGGAACUTsT 568 AGUUCCUUGUCAAAGCUCCTsT 14% 1% 14% 2% ND-8633569 AUACCCGUGCCCUCACAGATsT 570 UCUGUGAGGGCACGGGUAUTsT 21% 2% 16% 1%ND-8634 571 GGAGUGGCCAAAGUCAACATsT 572 UGUUGACUUUGGCCACUCCTsT 21% 3% 16%1% ND-8635 573 AACUACAAAACCAAUUCUGTsT 574 CAGAAUUGGUUUUGUAGUUTsT 49% 5%37% 3% ND-8636 575 UGCUGGAGUGUUGCUGUUGTsT 576 CAACAGCAACACUCCAGCATsT 27%3% 21% 2% ND-8637 577 AGGUCUCCUGCAACCAGGCTsT 578 GCCUGGUUGCAGGAGACCUTsT62% 8% 61% 4% ND-8638 579 CUUUGGCAUGAUGUACUGGTsT 580CCAGUACAUCAUGCCAAAGTsT 66% 6% 52% 8% ND-8639 581 CAUCUGCACCCUCAAUCCCTsT582 GGGAUUGAGGGUGCAGAUGTsT 50% 7% 40% 4% ND-8640 583CGACUGCACCAAGAAUGGCTsT 584 GCCAUUCUUGGUGCAGUCGTsT 67% 6% 54% 5% ND-8641585 AAAACACAACCAAGGGUACTsT 586 GUACCCUUGGUUGUGUUUUTsT 14% 2% 14% 1%ND-8642 587 CAUCUGCUGGAGUGUUGCUTsT 588 AGCAACACUCCAGCAGAUGTsT 13% 2% 13%1% ND-8643 589 CCUACAUCUUCUAUCCGCGTsT 590 CGCGGAUAGAAGAUGUAGGTsT 15% 4%13% 0% ND-8644 591 GCCUACAUCUUCUAUCCGCTsT 592 GCGGAUAGAAGAUGUAGGCTsT 14%3% 11% 1% ND-8645 593 GAGUGGUACCGCUUCCACUTsT 594 AGUGGAAGCGGUACCACUCTsT16% 0% 20% 1% ND-8646 595 GGUACCGCUUCCACUACAUTsT 596AUGUAGUGGAAGCGGUACCTsT 12% 0% 14% 1% ND-8647 597 GUGGUACCGCUUCCACUACTsT598 GUAGUGGAAGCGGUACCACTsT 42% 4% 44% 3% ND-8648 599GAAUUACUCUCACUUCCACTsT 600 GUGGAAGUGAGAGUAAUUCTsT 10% 1% 11% 3% ND-8649601 AAUUACUCUCACUUCCACCTsT 602 GGUGGAAGUGAGAGUAAUUTsT 105%  10%  102% 8% ND-8650 603 UACUCUCACUUCCACCACCTsT 604 GGUGGUGGAAGUGAGAGUATsT 55% 6%54% 8% ND-8651 605 AGUGGUACCGCUUCCACUATsT 606 UAGUGGAAGCGGUACCACUTsT 57%6% 59% 12%  ND-8652 607 GGGCAACUUCAUCUUCGCCTsT 608GGCGAAGAUGAAGUUGCCCTsT 47% 12%  36% 7%

Table 1B: Selected siRNAs in extended screening set (“human-only”siRNAs). A further 344 iRNA sequences were identified and were designedto be fully complementary to the human alpha-ENaC sequences, accordingto the design criteria described in the examples section. All siRNAslisted in this screening set were modified only with a phosphorothioatelinkage at the 3′-end between nucleotides 20 and 21 of each strand. Thepercentage residual expression of alpha-ENaC in single-dose transfectionassay is shown (refer to examples section for methods used).

TABLE 1B 1st screen single dose @ 50 nM in Duplex ID Seq ID Sense Seq IDAntisense H441; MV SD ND-10445 609 CUGCGGCUAAGUCUCUUUUTsT 610AAAAGAGACUUAGCCGCAGTsT 94% 8% ND-10446 611 AUCGCGACAGAACAAUUACTsT 612GUAAUUGUUCUGUCGCGAUTsT 13% 2% ND-10447 613 UCGCGACAGAACAAUUACATsT 614UGUAAUUGUUCUGUCGCGATsT 18% 1% ND-10448 615 CCCGUUUAUGUAUGCUCCATsT 616UGGAGCAUACAUAAACGGGTsT 41% 1% ND-10449 617 CCCGGGUAAGUAAAGGCAGTsT 618CUGCCUUUACUUACCCGGGTsT 23% 1% ND-10450 619 GGUACCCGGAAAUUAAAGATsT 620UCUUUAAUUUCCGGGUACCTsT 14% 2% ND-10451 621 GCUAUCGCGACAGAACAAUTsT 622AUUGUUCUGUCGCGAUAGCTsT 24% 2% ND-10452 623 UAUCGCGACAGAACAAUUATsT 624UAAUUGUUCUGUCGCGAUATsT 12% 1% ND-10453 625 UGCGGCUAAGUCUCUUUUUTsT 626AAAAAGAGACUUAGCCGCATsT 46% 3% ND-10454 627 GGCGAUUAUGGCGACUGCATsT 628UGCAGUCGCCAUAAUCGCCTsT 14% 0% ND-10455 629 AUGUCUAGCCCAUCAUCCUTsT 630AGGAUGAUGGGCUAGACAUTsT 12% 2% ND-10456 631 CUACAGGUACCCGGAAAUUTsT 632AAUUUCCGGGUACCUGUAGTsT 28% 2% ND-10457 633 CCGUCGAGCCCGUAGCGUGTsT 634CACGCUACGGGCUCGACGGTsT 27% 3% ND-10458 635 CGCGACAGAACAAUUACACTsT 636GUGUAAUUGUUCUGUCGCGTsT 39% 7% ND-10459 637 AGGUACCCGGAAAUUAAAGTsT 638CUUUAAUUUCCGGGUACCUTsT 30% 3% ND-10460 639 CAUGCACGGGUUUCCUGCCTsT 640GGCAGGAAACCCGUGCAUGTsT 95% 6% ND-10461 641 AGCUUGCGGGACAACAACCTsT 642GGUUGUUGUCCCGCAAGCUTsT 94% 8% ND-10462 643 ACUGCGGCUAAGUCUCUUUTsT 644AAAGAGACUUAGCCGCAGUTsT 13% 2% ND-10463 645 CAUCCCUUAGAACCCUGCUTsT 646AGCAGGGUUCUAAGGGAUGTsT 18% 1% ND-10464 647 ACCCGGGUAAGUAAAGGCATsT 648UGCCUUUACUUACCCGGGUTsT 41% 1% ND-10465 649 GAUUAUGGCGACUGCACCATsT 650UGGUGCAGUCGCCAUAAUCTsT 23% 1% ND-10466 651 CUCGGACAAGCUCGUCUUCTsT 652GAAGACGAGCUUGUCCGAGTsT 14% 2% ND-10467 653 GCGAUUAUGGCGACUGCACTsT 654GUGCAGUCGCCAUAAUCGCTsT 24% 2% ND-10468 655 AAUUACACCGUCAACAACATsT 656UGUUGUUGACGGUGUAAUUTsT 12% 1% ND-10469 657 AACUGCCGUUGAUGUGUGGTsT 658CCACACAUCAACGGCAGUUTsT 46% 3% ND-10470 659 AACUGCGGCUAAGUCUCUUTsT 660AAGAGACUUAGCCGCAGUUTsT 14% 0% ND-10471 661 CCGCUGAUAACCAGGACAATsT 662UUGUCCUGGUUAUCAGCGGTsT 12% 2% ND-10472 663 AAGGGUACACGCAGGCAUGTsT 664CAUGCCUGCGUGUACCCUUTsT 28% 2% ND-10473 665 CCGGGUAAGUAAAGGCAGATsT 666UCUGCCUUUACUUACCCGGTsT 27% 3% ND-10474 667 CCCAUACCAGGUCUCAUGGTsT 668CCAUGAGACCUGGUAUGGGTsT 39% 7% ND-10475 669 AUUAUGGCGACUGCACCAATsT 670UUGGUGCAGUCGCCAUAAUTsT 30% 3% ND-10476 671 AUGCACGGGUUUCCUGCCCTsT 672GGGCAGGAAACCCGUGCAUTsT 95% 6% ND-10477 673 CUAGCCCUCCACAGUCCACTsT 674GUGGACUGUGGAGGGCUAGTsT 43% 7% ND-10478 675 CAGGUACCCGGAAAUUAAATsT 676UUUAAUUUCCGGGUACCUGTsT 11% 1% ND-10479 677 AAUACAGCUCCUUCACCACTsT 678GUGGUGAAGGAGCUGUAUUTsT 30% 3% ND-10480 679 CACGGGUUUCCUGCCCAGCTsT 680GCUGGGCAGGAAACCCGCGTsT 19% 1% ND-10481 681 GGACUGAAUCUUGCCCGUUTsT 682AACGGGCAAGAUUCAGUCCTsT 14% 2% ND-10482 683 CGUUUAUGUAUGCUCCAUGTsT 684CAUGGAGCAUACAUAAACGTsT 15% 1% ND-10483 685 GGGUACUGCUACUAUAAGCTsT 686GCUUAUAGUAGCAGUACCCTsT 11% 0% ND-10484 687 UCGGUGUUGUCUGUGGUGGTsT 688CCACCACAGACAACACCGATsT 65% 5% ND-10485 689 AAACUGCCGUUGAUGUGUGTsT 690CACACAUCAACGGCAGUUUTsT 73% 6% ND-10486 691 GCGAAACUUGGAGCUUUGATsT 692UCAAAGCUCCAAGUUUCGCTsT  8% 1% ND-10487 693 GGCCCGUCGAGCCCGUAGCTsT 694GCUACGGGCUCGACGGGCCTsT 26% 3% ND-10488 695 GCGACAGAACAAUUACACCTsT 696GGUGUAAUUGUUCUGUCGCTsT 10% 2% ND-10489 697 GCGACGGCUUAAGCCAGCCTsT 698GGCUGGCUUAAGCCGUCGCTsT 50% 1% ND-10490 699 GACCCGGGUAAGUAAAGGCTsT 700GCCUUUACUUACCCGGGUCTsT 74% 1% ND-10491 701 UUGAUCACUCCGCCUUCUCTsT 702GAGAAGGCGGAGUGAUCAATsT 80% 7% ND-10492 703 UCUAGCCCUCCACAGUCCATsT 704UGGACUGUGGAGGGCUAGATsT 69% 4% ND-10493 705 GUUUCACCAAGUGCCGGAATsT 706UUCCGGCACUUGGUGAAACTsT 23% 3% ND-10494 707 CUCAACUCGGACAAGCUCGTsT 708CGAGCUUGUCCGAGUUGAGTsT 45% 6% ND-10495 709 CAACUCGGACAAGCUCGUCTsT 710GACGAGCUUGUCCGAGUUGTsT 23% 3% ND-10496 711 ACCCGGAAAUUAAAGAGGATsT 712UCCUCUUUAAUUUCCGGGUTsT 13% 2% ND-10497 713 CCCGGAAAUUAAAGAGGAGTsT 714CUCCUCUUUAAUUUCCGGGTsT 19% 1% ND-10498 715 CACCACUCUCGUGGCCGGCTsT 716GCCGGCCACGAGAGUGGUGTsT 94% 11%  ND-10499 717 CGUCGAGCCCGUAGCGUGGTsT 718CCACGCUACGGGCUCGACGTsT 13% 1% ND-10500 719 GCUUGCGGGACAACAACCCTsT 720GGGUUGUUGUCCCGCAAGCTsT 49% 2% ND-10501 721 GAAUCAACAACGGUCUGUCTsT 722GACAGACCGUUGUUGAUUCTsT 18% 2% ND-10502 723 GGGCGAUUAUGGCGACUGCTsT 724GCAGUCGCCAUAAUCGCCCTsT  8% 1% ND-10503 725 CGAUUAUGGCGACUGCACCTsT 726GGUGCAGUCGCCAUAAUCGTsT 17% 1% ND-10504 727 UCUGCUGGUUACUCACGAUTsT 728AUCGUGAGUAACCAGCAGATsT 38% 4% ND-10505 729 CUAUCGCGACAGAACAAUUTsT 730AAUUGUUCUGUCGCGAUAGTsT  9% 1% ND-10506 731 CAAUUACACCGUCAACAACTsT 732GUUGUUGACGGUGUAAUUGTsT 11% 1% ND-10507 733 ACCGUCAACAACAAGAGAATsT 734UUCUCUUGUUGUUGACGGUTsT  9% 1% ND-10508 735 CUCCUCGGUGUUGUCUGUGTsT 736CACAGACAACACCGAGGAGTsT 78% 5% ND-10509 737 GGAGGUAGCCUCCACCCUGTsT 738CAGGGUGGAGGCUACCUCCTsT 18% 1% ND-10510 739 GGAGAGGUUUCUCACACCATsT 740UGGUGUGAGAAACCUCUCCTsT 13% 1% ND-10511 741 CUGCCGUUGAUGUGUGGAGTsT 742CUCCACACAUCAACGGCAGTsT 19% 2% ND-10512 743 UGCCGUUGAUGUGUGGAGGTsT 744CCUCCACACAUCAACGGCATsT 82% 4% ND-10513 745 AGAUGGGUAAGGGCUCAGGTsT 746CCUGAGCCCUUACCCAUCUTsT 24% 1% ND-10514 747 AGAACAGUAGCUGAUGAAGTsT 748CUUCAUCAGCUACUGUUCUTsT 15% 0% ND-10515 749 GCGGCUAAGUCUCUUUUUCTsT 750GAAAAAGAGACUUAGCCGCTsT 13% 1% ND-10516 751 CCUAAGAAACCGCUGAUAATsT 752UUAUCAGCGGUUUCUUAGGTsT  6% 0% ND-10517 753 GAAACCGCUGAUAACCAGGTsT 754CCUGGUUAUCAGCGGUUUCTsT 13% 0% ND-10518 755 AACCGCUGAUAACCAGGACTsT 756GUCCUGGUUAUCAGCGGUUTsT 42% 2% ND-10519 757 ACCGCUGAUAACCAGGACATsT 758UGUCCUGGUUAUCAGCGGUTsT 11% 1% ND-10520 759 CCAAGGGUACACGCAGGCATsT 760UGCCUGCGUGUACCCUUGGTsT 19% 1% ND-10521 761 CAAGGGUACACGCAGGCAUTsT 762AUGCCUGCGUGUACCCUUGTsT 12% 0% ND-10522 763 AGGGUACACGCAGGCAUGCTsT 764GCAUGCCUGCGUGUACCCUTsT 23% 1% ND-10523 765 GUACACGCAGGCAUGCACGTsT 766CGUGCAUGCCUGCGUGUACTsT 27% 1% ND-10524 767 AGGCAUGCACGGGUUUCCUTsT 768AGGAAACCCGUGCAUGCCUTsT 14% 0% ND-10525 769 GGCAUGCACGGGUUUCCUGTsT 770CAGGAAACCCGUGCAUGCCTsT 18% 3% ND-10526 771 ACGGGUUUCCUGCCCAGCGTsT 772CGCUGGGCAGGAAACCCGUTsT 30% 1% ND-10527 773 GAGCAGACCCGGGUAAGUATsT 774UACUUACCCGGGUCUGCUCTsT 24% 2% ND-10528 775 AGCAGACCCGGGUAAGUAATsT 776UUACUUACCCGGGUCUGCUTsT 24% 2% ND-10529 777 GGGUAAGUAAAGGCAGACCTsT 778GGUCUGCCUUUACUUACCCTsT 39% 3% ND-10530 779 AGCCUCAUACCCGUGCCCUTsT 780AGGGCACGGGUAUGAGGCUTsT 82% 5% ND-10531 781 GUGAACGCUUCUGCCACAUTsT 782AUGUGGCAGAAGCGUUCACTsT 13% 1% ND-10532 783 AAAUUGAUCACUCCGCCUUTsT 784AAGGCGGAGUGAUCAAUUUTsT 18% 2% ND-10533 785 AAUUGAUCACUCCGCCUUCTsT 786GAAGGCGGAGUGAUCAAUUTsT 19% 0% ND-10534 787 GCCUUGCGGUCAGGGACUGTsT 788CAGUCCCUGACCGCAAGGCTsT 12% 1% ND-10535 789 CUUGCGGUCAGGGACUGAATsT 790UUCAGUCCCUGACCGCAAGTsT 11% 0% ND-10536 791 UUGCGGUCAGGGACUGAAUTsT 792AUUCAGUCCCUGACCGCAATsT 12% 0% ND-10537 793 AUGUAUGCUCCAUGUCUAGTsT 794CUAGACAUGGAGCAUACAUTsT 21% 1% ND-10538 795 AGCAAGUAGGCAGGAGCUCTsT 796GAGCUCCUGCCUACUUGCUTsT 19% 1% ND-10539 797 CAGCCCAUACCAGGUCUCATsT 798UGAGACCUGGUAUGGGCUGTsT 27% 2% ND-10540 799 CAGCCGUCGCGACCUGCGGTsT 800CCGCAGGUCGCGACGGCUGTsT 44% 4% ND-10541 801 GGGCCCGUCGAGCCCGUAGTsT 802CUACGGGCUCGACGGGCCCTsT 71% 6% ND-10542 803 CGUAGCGUGGCCUCCAGCUTsT 804AGCUGGAGGCCACGCUACGTsT 84% 9% ND-10543 805 GGUGAGGGAGUGGUACCGCTsT 806GCGGUACCACUCCCUCACCTsT 108%  8% ND-10544 807 AAAGUACACACAGCAGGUGTsT 808CACCUGCUGUGUGUACUUUTsT 140%  7% ND-10545 809 CCAGGUUGACUUCUCCUCATsT 810UGAGGAGAAGUCAACCUGGTsT 18% 2% ND-10546 811 UGUUUCACCAAGUGCCGGATsT 812UCCGGCACUUGGUGAAACATsT 31% 2% ND-10547 813 UGCUGGUUACUCACGAUGGTsT 814CCAUUGUGAGUAACCAGCATsT 144%  10%  ND-10548 815 UCCUCGGUGUUGUCUGUGGTsT816 CCACAGACAACACCGAGGATsT 106%  14%  ND-10549 817AGGUAGCCUCCACCCUGGCTsT 818 GCCAGGGUGGAGGCUACCUTsT 74% 15%  ND-10550 819GCCGUUGAUGUGUGGAGGGTsT 820 CCCUCCACACAUCAACGGCTsT 26% 4% ND-10551 821GAUGGGUAAGGGCUCAGGATsT 822 UCCUGAGCCCUUACCCAUCTsT 22% 1% ND-10552 823CCCAACUGCGGCUAAGUCUTsT 824 AGACUUAGCCGCAGUUGGGTsT 18% 2% ND-10553 825CCAAGCGAAACUUGGAGCUTsT 826 AGCUCCAAGUUUCGCUUGGTsT 16% 1% ND-10554 827GGGUACACGCAGGCAUGCATsT 828 UGCAUGCCUGCGUGUACCCTsT 19% 2% ND-10555 829UGCACGGGUUUCCUGCCCATsT 830 UGGGCAGGAAACCCGUGCATsT 28% 2% ND-10556 831CUCCUCUAGCCUCAUACCCTsT 832 GGGUAUGAGGCUAGAGGAGTsT 109%  8% ND-10557 833UCCUCUAGCCUCAUACCCGTsT 834 CGGGUAUGAGGCUAGAGGATsT 117%  7% ND-10558 835UCUAGCCUCAUACCCGUGCTsT 836 GCACGGGUAUGAGGCUAGATsT 128%  9% ND-10559 837UUCAUACCUCUACAUGUCUTsT 838 AGACAUGUAGAGGUAUGAATsT 52% 4% ND-10560 839UCUACAUGUCUGCUUGAGATsT 840 UCUCAAGCAGACAUGUAGATsT 15% 2% ND-10561 841AUAUUUCCUCAGCCUGAAATsT 842 UUUCAGGCUGAGGAAAUAUTsT 15% 2% ND-10562 843AACUCCUAUGCAUCCCUUATsT 844 UAAGGGAUGCAUAGGAGUUTsT 14% 1% ND-10563 845GCAUCCCUUAGAACCCUGCTsT 846 GCAGGGUUCUAAGGGAUGCTsT 20% 1% ND-10564 847UGAUCACUCCGCCUUCUCCTsT 848 GGAGAAGGCGGAGUGAUCATsT 67% 7% ND-10565 849UGUAAGUGCCUUGCGGUCATsT 850 UGACCGCAAGGCACUUACATsT 17% 2% ND-10566 851CCUUGCGGUCAGGGACUGATsT 852 UCAGUCCCUGACCGCAAGGTsT 14% 1% ND-10567 853AAUCUUGCCCGUUUAUGUATsT 854 UACAUAAACGGGCAAGAUUTsT 13% 2% ND-10568 855CCGUUUAUGUAUGCUCCAUTsT 856 AUGGAGCAUACAUAAACGGTsT 19% 6% ND-10569 857UGUAUGCUCCAUGUCUAGCTsT 858 GCUAGACAUGGAGCAUACATsT 87% 13%  ND-10570 859CAUGUCUAGCCCAUCAUCCTsT 860 GGAUGAUGGGCUAGACAUGTsT 33% 4% ND-10571 861AGUAGGCAGGAGCUCAAUATsT 862 UAUUGAGCUCCUGCCUACUTsT 11% 1% ND-10572 863CCUACAGGUACCCGGAAAUTsT 864 AUUUCCGGGUACCUGUAGGTsT 22% 3% ND-10573 865CCCGUCGAGCCCGUAGCGUTsT 866 ACGCUACGGGCUCGACGGGTsT 23% 1% ND-10574 867GCGGUGAGGGAGUGGUACCTsT 868 GGUACCACUCCCUCACCGCTsT 30% 1% ND-10575 869UUAUGGCGACUGCACCAAGTsT 870 CUUGGUGCAGUCGCCAUAATsT 77% 6% ND-10576 871CUAUAAGCUCCAGGUUGACTsT 872 GUCAACCUGGAGCUUAUAGTsT 11% 1% ND-10577 873UAUAAGCUCCAGGUUGACUTsT 874 AGUCAACCUGGAGCUUAUATsT 42% 8% ND-10578 875AGGUUGACUUCUCCUCAGATsT 876 UCUGAGGAGAAGUCAACCUTsT 13% 3% ND-10579 877CUGGGCUGUUUCACCAAGUTsT 878 ACUUGGUGAAACAGCCCAGTsT 19% 6% ND-10580 879AACAAUUACACCGUCAACATsT 880 UGUUGACGGUGUAAUUGUUTsT 13% 1% ND-10581 881UGGGUAAGGGCUCAGGAAGTsT 882 CUUCCUGAGCCCUUACCCATsT 20% 3% ND-10582 883GGGUAAGGGCUCAGGAAGUTsT 884 ACUUCCUGAGCCCUUACCCTsT 22% 3% ND-10583 885CACCCAACUGCGGCUAAGUTsT 886 ACUUAGCCGCAGUUGGGUGTsT 22% 10%  ND-10584 887ACCCAACUGCGGCUAAGUCTsT 888 GACUUAGCCGCAGUUGGGUTsT 22% 5% ND-10585 889CCAACUGCGGCUAAGUCUCTsT 890 GAGACUUAGCCGCAGUUGGTsT 14% 2% ND-10586 891CUUGGAUCAGCCAAGCGAATsT 892 UUCGCUUGGCUGAUCCAAGTsT 15% 1% ND-10587 893GCCAAGCGAAACUUGGAGCTsT 894 GCUCCAAGUUUCGCUUGGCTsT 17% 2% ND-10588 895UCCUAAGAAACCGCUGAUATsT 896 UAUCAGCGGUUUCUUAGGATsT 11% 2% ND-10589 897GCAUGCACGGGUUUCCUGCTsT 898 GCAGGAAACCCGUGCAUGCTsT 24% 8% ND-10590 899UGUUACUUAGGCAAUUCCCTsT 900 GGGAAUUGCCUAAGUAACATsT 48% 10%  ND-10591 901CUAGGGCUAGAGCAGACCCTsT 902 GGGUCUGCUCUAGCCCUAGTsT 58% 10%  ND-10592 903CUCUAGCCUCAUACCCGUGTsT 904 CACGGGUAUGAGGCUAGAGTsT 34% 5% ND-10593 905UUAGAACCCUGCUCAGACATsT 906 UGUCUGAGCAGGGUUCUAATsT 14% 1% ND-10594 907UGUGAACGCUUCUGCCACATsT 908 UGUGGCAGAAGCGUUCACATsT 15% 0% ND-10595 909AUUGAUCACUCCGCCUUCUTsT 910 AGAAGGCGGAGUGAUCAAUTsT 43% 1% ND-10596 911UCACUCCGCCUUCUCCUGGTsT 912 CCAGGAGAAGGCGGAGUGATsT 90% 5% ND-10597 913GCGGUCAGGGACUGAAUCUTsT 914 AGAUUCAGUCCCUGACCGCTsT 11% 0% ND-10598 915GGUCAGGGACUGAAUCUUGTsT 916 CAAGAUUCAGUCCCUGACCTsT 13% 1% ND-10599 917GUAUGCUCCAUGUCUAGCCTsT 918 GGCUAGACAUGGAGCAUACTsT 28% 3% ND-10600 919CCAUGUCUAGCCCAUCAUCTsT 920 GAUGAUGGGCUAGACAUGGTsT 12% 1% ND-10601 921GAUCGAGUUCCACCGCUCCTsT 922 GGAGCGGUGGAACUCGAUCTsT 17% 1% ND-10602 923GGACUCUAGCCCUCCACAGTsT 924 CUGUGGAGGGCUAGAGUCCTsT 41% 4% ND-10603 925UCACCACUCUCGUGGCCGGTsT 926 CCGGCCACGAGAGUGGUGATsT 83% 3% ND-10604 927CAGCUUGCGGGACAACAACTsT 928 GUUGUUGUCCCGCAAGCUGTsT 21% 1% ND-10605 929CAUCUUCUAUCCGCGGCCCTsT 930 GGGCCGCGGAUAGAAGAUGTsT 26% 2% ND-10606 931AUAAGCUCCAGGUUGACUUTsT 932 AAGUCAACCUGGAGCUUAUTsT 15% 1% ND-10607 933CUGCUGGUUACUCACGAUGTsT 934 CAUCGUGAGUAACCAGCAGTsT 85% 8% ND-10608 935GAACAAUUACACCGUCAACTsT 936 GUUGACGGUGUAAUUGUUCTsT 13% 1% ND-10609 937AUUACACCGUCAACAACAATsT 938 UUGUUGUUGACGGUGUAAUTsT 12% 0% ND-10610 939CUGUGGUUCGGCUCCUCGGTsT 940 CCGAGGAGCCGAACCACAGTsT 53% 2% ND-10611 941GAAGUGCCUUGGCUCCAGCTsT 942 GCUGGAGCCAAGGCACUUCTsT 24% 3% ND-10612 943GAUCAGCCAAGCGAAACUUTsT 944 AAGUUUCGCUUGGCUGAUCTsT 12% 0% ND-10613 945AGAAACCGCUGAUAACCAGTsT 946 CUGGUUAUCAGCGGUUUCUTsT 12% 1% ND-10614 947UGAUAACCAGGACAAAACATsT 948 UGUUUUGUCCUGGUUAUCATsT 7% 1% ND-10615 949CACGCAGGCAUGCACGGGUTsT 950 ACCCGUGCAUGCCUGCGUGTsT 12% 0% ND-10616 951GCUCUCCAGUAGCACAGAUTsT 952 AUCUGUGCUACUGGAGAGCTsT  9% 0% ND-10617 953CAGACCCGGGUAAGUAAAGTsT 954 CUUUACUUACCCGGGUCUGTsT 55% 3% ND-10618 955AGACCCGGGUAAGUAAAGGTsT 956 CCUUUACUUACCCGGGUCUTsT 72% 8% ND-10619 957AUCACUCCGCCUUCUCCUGTsT 958 CAGGAGAAGGCGGAGUGAUTsT 63% 6% ND-10620 959CACUCCGCCUUCUCCUGGGTsT 960 CCCAGGAGAAGGCGGAGUGTsT 28% 1% ND-10621 961AACUAGACUGUAAGUGCCUTsT 962 AGGCACUUACAGUCUAGUUTsT 23% 1% ND-10622 963UAUGCUCCAUGUCUAGCCCTsT 964 GGGCUAGACAUGGAGCAUATsT 98% 2% ND-10623 965CCCGAUGUAUGGAAACUGCTsT 966 GCAGUUUCCAUACAUCGGGTsT 11% 1% ND-10624 967GUACUGCUACUAUAAGCUCTsT 968 GAGCUUAUAGUAGCAGUACTsT 19% 1% ND-10625 969AGCGUGACCAGCUACCAGCTsT 970 GCUGGUAGCUGGUCACGCUTsT 49% 2% ND-10626 971ACAAUUACACCGUCAACAATsT 972 UUGUUGACGGUGUAAUUGUTsT  8% 0% ND-10627 973AUGCUCCUCUGGUGGGAGGTsT 974 CCUCCCACCAGAGGAGCAUTsT 76% 5% ND-10628 975AACAGUAGCUGAUGAAGCUTsT 976 AGCUUCAUCAGCUACUGUUTsT 22% 1% ND-10629 977CUGACUCCCGAGGGCUAGGTsT 978 CCUAGCCCUCGGGAGUCAGTsT 34% 2% ND-10630 979GUGCAACCAGAACAAAUCGTsT 980 CGAUUUGUUCUGGUUGCACTsT 10% 1% ND-10631 981UGCAACCAGAACAAAUCGGTsT 982 CCGAUUUGUUCUGGUUGCATsT 48% 4% ND-10632 983CUUCAAAGUACACACAGCATsT 984 UGCUGUGUGUACUUUGAAGTsT 20% 1% ND-10633 985CAGCGUGACCAGCUACCAGTsT 986 CUGGUAGCUGGUCACGCUGTsT 35% 1% ND-10634 987AGAACAAUUACACCGUCAATsT 988 UUGACGGUGUAAUUGUUCUTsT 14% 0% ND-10635 989GAUAACCAGGACAAAACACTsT 990 GUGUUUUGUCCUGGUUAUCTsT 11% 1% ND-10636 991ACAACCAAGGGUACACGCATsT 992 UGCGUGUACCCUUGGUUGUTsT 17% 1% ND-10637 993CCCAGCGACGGCUUAAGCCTsT 994 GGCUUAAGCCGUCGCUGGGTsT 27% 2% ND-10638 995CUCCCGAGGGCUAGGGCUATsT 996 UAGCCCUAGCCCUCGGGAGTsT 23% 1% ND-10639 997UAGAACCCUGCUCAGACACTsT 998 GUGUCUGAGCAGGGUUCUATsT 35% 2% ND-10640 999CCUGGGCUGUUUCACCAAGTsT 1000 CUUGGUGAAACAGCCCAGGTsT 14% 1% ND-10641 1001 GGAUCAGCCAAGCGAAACUTsT 1002  AGUUUCGCUUGGCUGAUCCTsT 16% 3% ND-106421003  AAGAAACCGCUGAUAACCATsT 1004  UGGUUAUCAGCGGUUUCUUTsT 17% 1%ND-10643 1005  ACCAAGGGUACACGCAGGCTsT 1006  GCCUGCGUGUACCCUUGGUTsT 37%4% ND-10644 1007  GUAGCACAGAUGUCUGCUCTsT 1008  GAGCAGACAUCUGUGCUACTsT13% 3% ND-10645 1009  UUUCAUACCUCUACAUGUCTsT 1010 GACAUGUAGAGGUAUGAAATsT 88% 8% ND-10646 1011  CCAACCAUCUGCCAGAGAATsT1012  UUCUCUGGCAGAUGGUUGGTsT 16% 2% ND-10647 1013 GUCAGGGACUGAAUCUUGCTsT 1014  GCAAGAUUCAGUCCCUGACTsT 16% 3% ND-106481015  AGCAUGAUCAAGGAGUGUGTsT 1016  CACACUCCUUGAUCAUGCUTsT 50% 7%ND-10649 1017  GCAGCGUGACCAGCUACCATsT 1018  UGGUAGCUGGUCACGCUGCTsT 40%6% ND-10650 1019  CAGCUCUCUGCUGGUUACUTsT 1020  AGUAACCGACAGAGAGCUGTsT56% 5% ND-10651 1021  GUUCGGCUCCUCGGUGUUGTsT 1022 CAACACCGAGGAGCCGAACTsT 68% 5% ND-10652 1023  GCAGAUGCUCCUCUGGUGGTsT1024  CCACCAGAGGAGCAUCUGCTsT 26% 5% ND-10653 1025 AGGAAGUUGCUCCAAGAACTsT 1026  GUUCUUGGAGCAACUUCCUTsT 18% 2% ND-106541027  AACGCUUCUGCCACAUCUUTsT 1028  AAGAUGUGGCAGAAGCGUUTsT 18% 1%ND-10655 1029  CACCUGGGCUGUUUCACCATsT 1030  UGGUGAAACAGCCCAGGUGTsT 17%2% ND-10656 1031  AAGCCAUGCAGCGUGACCATsT 1032  UGGUCACGCUGCAUGGCUUTsT27% 3% ND-10657 1033  CGAGGGCUAGGGCUAGAGCTsT 1034 GCUCUAGCCCUAGCCCUCGTsT 30% 1% ND-10658 1035  GGAAACCCUGGACAGACUUTsT1036  AAGUCUGUCCAGGGUUUCCTsT 14% 1% ND-10659 1037 GUAGCUGAUGAAGCUGCCCTsT 1038  GGGCAGCUUCAUCAGCUACTsT 19% 1% ND-106601039  UCUUUUUCCCUUGGAUCAGTsT 1040  CUGAUCCAAGGGAAAAAGATsT 88% 4%ND-10661 1041  CUCCAGUAGCACAGAUGUCTsT 1042  GACAUCUGUGCUACUGGAGTsT 10%1% ND-10662 1043  CCAAAAUUGAUCACUCCGCTsT 1044  GCGGAGUGAUCAAUUUUGGTsT25% 3% ND-10663 1045  CAGACCACCUGGGCUGUUUTsT 1046 AAACAGCCCAGGUGGUCUGTsT 24% 2% ND-10664 1047  CCCUUCCCAACUAGACUGUTsT1048  ACAGUCUAGUUGGGAAGGGTsT 15% 2% ND-10665 1049 CGCAGCCGUCGCGACCUGCTsT 1050  GCAGGUCGCGACGGCUGCGTsT 45% 2% ND-106661051  UUCUCACACCAAGGCAGAUTsT 1052  AUCUGCCUUGGUGUGAGAATsT 25% 2%ND-10667 1053  CACCACCAUCCACGGCGCCTsT 1054  GGCGCCGUGGAUGGUGGUGTsT 35%3% ND-10668 1055  CCAUUACUUUUGUGAACGCTsT 1056  GCGUUCACAAAAGUAAUGGTsT19% 4% 2nd screen single dose @ 50 nM in H441; MV SD ND-10669 1057 CCAAGAACAGUAGCUGAUGTsT 1058  CAUCAGCUACUGUUCUUGGTsT 23% 4% 16% 2%ND-10670 1059  AGGAGAGGUUUCUCACACCTsT 1060  GGUGUGAGAAACCUCUCCUTsT 18%3% 17% 1% ND-10671 1061  AUCAUCCUGCUUGGAGCAATsT 1062 UUGCUCCAAGCAGGAUGAUTsT 33% 3% 24% 2% ND-10672 1063 GCAUCACAGAGCAGACGCUTsT 1064  AGCGUCUGCUCUGUGAUGCTsT 29% 2% 27% 4%ND-10673 1065  AGGAGGUAGCCUCCACCCUTsT 1066  AGGGUGGAGGCUACCUCCUTsT 63%6% 61% 3% ND-10674 1067  ACAACCGCAUGAAGACGGCTsT 1068 GCCGUCUUCAUGCGGUUGCTsT 94% 2% ND-10675 1069  GCAUGAAGACGGCCUUCUGTsT1070  CAGAAGGCCGUCUUCAUGCTsT 20% 2% 18% 1% ND-10676 1071 GUCACGAUGGUCACCCUCCTsT 1072  GGAGGGUGACCAUCGUGACTsT 66% 5% 60% 4%ND-10677 1073  CCCUGCUCAGACACCAUUATsT 1074  UAAUGGUGUCUGAGCAGGGTsT 15%3% 18% 1% ND-10678 1075  UCACGAUGGUCACCCUCCUTsT 1076 AGGAGGGUGACCAUCGUGATsT 80% 6% 70% 4% ND-10679 1077 UCAACCUCAACUCGGACAATsT 1078  UUGUCCGAGUUGAGGUUGATsT 20% 3% 21% 1%ND-10680 1079  UGACCAGCUACCAGCUCUCTsT 1080  GAGAGCUGGUAGCUGGUCATsT 88%22%  77% 5% ND-10681 1081  GAUGGCCCUCGGUGACAUCTsT 1082 GAUGUCACCGAGGGCCAUCTsT 88% 18%  60% 4% ND-10682 1083 GCUUUGACAAGGAACUUUCTsT 1084  GAAAGUUCCUUGUCAAAGCTsT 19% 7% 14% 2%ND-10683 1085  CGAUACUGGUCUCCAGGCCTsT 1086  GGCCUGGAGACCAGUAUCGTsT 27%5% 27% 2% ND-10684 1087  UCUGGAUGUCUUCCAUGCCTsT 1088 GGCAUGGAAGACAUCCAGATsT 92% 13%  89% 3% ND-10685 1089 CAGGACCCUAGACCUCUGCTsT 1090  GCAGAGGUCUAGGGUCCUGTsT 58% 14%  50% 2%ND-10686 1091  GACCCUAGACCUCUGCAGCTsT 1092  GCUGCAGAGGUCUAGGGUCTsT 27%2% ND-10687 1093  ACCCUAGACCUCUGCAGCCTsT 1094  GGCUGCAGAGGUCUAGGGUTsT21% 1% ND-10688 1095  CAGCCCACGGCGGAGGAGGTsT 1096 CCUCCUCCGCCGUGGGCUGTsT 55% 4% ND-10689 1097  CUCUUCGAGUUCUUCUGCATsT1098  UGCAGAAGAACUCGAAGAGTsT 13% 3% ND-10690 1099 UUGGCAUGAUGUACUGGCATsT 1100  UGCCAGUACAUCAUGCCAATsT 16% 2% ND-106911101  GGCAUGAUGUACUGGCAAUTsT 1102  AUUGCCAGUACAUCAUGCCTsT 13% 1%ND-10692 1103  UGUACUGGCAAUUCGGCCUTsT 1104  AGGCCGAAUUGCCAGUACATsT 45%2% ND-10693 1105  ACUGGCAAUUCGGCCUGCUTsT 1106  AGCAGGCCGAAUUGCCAGUTsT38% 3% ND-10694 1107  GGCAAUUCGGCCUGCUUUUTsT 1108 AAAAGCAGGCCGAAUUGCCTsT 10% 1% ND-10695 1109  CAAUUCGGCCUGCUUUUCGTsT1110  CGAAAAGCAGGCCGAAUUGTsT 12% 1% ND-10696 1111 UCGGAGAGUACUUCAGCUATsT 1112  UAGCUGAAGUACUCUCCGATsT 12% 1% ND-106971113  CAACAUCCUGUCGAGGCUGTsT 1114  CAGCCUCGACAGGAUGUUGTsT 35% 7%ND-10698 1115  CAUCCUGUCGAGGCUGCCATsT 1116  UGGCAGCCUCGACAGGAUGTsT 26%6% ND-10699 1117  UCCUGCAACCAGGCGAAUUTsT 1118  AAUUCGCCUGGUUGCAGGATsT28% 6% ND-10700 1119  GGAAACUGCUAUACUUUCATsT 1120 UGAAAGUAUAGCAGUUUCCTsT  7% 2% ND-10701 1121  ACGGUCUGUCCCUGAUGCUTsT1122  AGCAUCAGGGACAGACCGUTsT 28% 7% ND-10702 1123 GGUCUGUCCCUGAUGCUGCTsT 1124  GCAGCAUCAGGGACAGACCTsT 33% 2% ND-107031125  GGCCCGGGUAAUGGUGCACTsT 1126  GUGCACCAUUACCCGGGCCTsT 47% 10% ND-10704 1127  CAGGAUGAACCUGCCUUUATsT 1128  UAAAGGCAGGUUCAUCCUGTsT 59%2% ND-10705 1129  GAUGAACCUGCCUUUAUGGTsT 1130  CCAUAAAGGCAGGUUCAUCTsT77% 7% ND-10706 1131  GGUGGCUUUAACUUGCGGCTsT 1132 GCCGCAAGUUAAAGCCACCTsT 47% 8% ND-10707 1133  GUGGCUUUAACUUGCGGCCTsT1134  GGCCGCAAGUUAAAGCCACTsT 17% 2% ND-10708 1135 UUGCGGCCUGGCGUGGAGATsT 1136  UCUCCACGCCAGGCCGCAATsT 52% 3% ND-107091137  UGCGGCCUGGCGUGGAGACTsT 1138  GUCUCCACGCCAGGCCGCATsT 81% 4%ND-10710 1139  GCGGCCUGGCGUGGAGACCTsT 1140  GGUCUCCACGCCAGGCCGCTsT 57%4% ND-10711 1141  CAGGUGUGUAUUCACUCCUTsT 1142  AGGAGUGAAUACACACCUGTsT24% 2% ND-10712 1143  GUGUAUUCACUCCUGCUUCTsT 1144 GAAGCAGGAGUGAAUACACTsT 20% 1% ND-10713 1145  GGCCCUCGGUGACAUCCCATsT1146  UGGGAUGUCACCGAGGGCCTsT 40% 3% ND-10714 1147 GAUGCUAUCGCGACAGAACTsT 1148  GUUCUGUCGCGAUAGCAUCTsT 24% 2% ND-107151149  ACUACAAAACCAAUUCUGATsT 1150  UCAGAAUUGGUUUUGUAGUTsT 19% 2%ND-10716 1151  CAAUUCUGAGUCUCCCUCUTsT 1152  AGAGGGAGACUCAGAAUUGTsT 35%3% ND-10717 1153  CUCUGUCACGAUGGUCACCTsT 1154  GGUGACCAUCGUGACAGAGTsT41% 4% ND-10718 1155  CUGCUCCGAAGGUUCCGAATsT 1156 UUCGGAACCUUCGGAGCAGTsT 16% 3% ND-10719 1157  AGGUUCCGAAGCCGAUACUTsT1158  AGUAUCGGCUUCGGAACCUTsT 16% 2% ND-10720 1159 GUUCCGAAGCCGAUACUGGTsT 1160  CCAGUAUCGGCUUCGGAACTsT 21% 2% ND-107211161  CGAAGCCGAUACUGGUCUCTsT 1162  GAGACCAGUAUCGGCUUCGTsT 16% 1%ND-10722 1163  AAGAUUGAAGGAUGUGCAGTsT 1164  CUGCACAUCCUUCAAUCUUTsT 25%2% ND-10723 1165  GAUUGAAGGAUGUGCAGGGTsT 1166  CCCUGCACAUCCUUCAAUCTsT26% 1% ND-10724 1167  UGCCUCUGAACACUCUGGUTsT 1168 ACCAGAGUGUUCAGAGGCATsT 45% 3% ND-10725 1169  CCUCUGAACACUCUGGUUUTsT1170  AAACCAGAGUGUUCAGAGGTsT 15% 2% ND-10726 1171 GACAAGGAACUUUCCUAAGTsT 1172  CUUAGGAAAGUUCCUUGUCTsT 105%  14%  ND-107271173  CAGGACAAAACACAACCAATsT 1174  UUGGUUGUGUUUUGUCCUGTsT 32% 5%ND-10728 1175  AACACAACCAAGGGUACACTsT 1176  GUGUACCCUUGGUUGUGUUTsT 60%13%  ND-10729 1177  UUGAACUUGGGUGGGAAACTsT 1178  GUUUCCCACCCAAGUUCAATsT23% 8% ND-10730 1179  UGAACUUGGGUGGGAAACCTsT 1180 GGUUUCCCACCCAAGUUCATsT 18% 4% ND-10731 1181  ACCCGUGCCCUCACAGAGCTsT1182  GCUCUGUGAGGGCACGGGUTsT 19% 1% ND-10732 1183 ACUAUAACAUCUGCUGGAGTsT 1184  CUCCAGCAGAUGUUAUAGUTsT 17% 5% ND-107331185  AUCUGCUGGAGUGUUGCUGTsT 1186  CAGCAACACUCCAGCAGAUTsT 119%  20% ND-10734 1187  CUGCUGGAGUGUUGCUGUUTsT 1188  AACAGCAACACUCCAGCAGTsT 58%13%  ND-10735 1189  CUAGCCCAUCAUCCUGCUUTsT 1190  AAGCAGGAUGAUGGGCUAGTsT20% 6% ND-10736 1191  CUCUGGAUGUCUUCCAUGCTsT 1192 GCAUGGAAGACAUCCAGAGTsT 28% 8% ND-10737 1193  AGCAGGACCCUAGACCUCUTsT1194  AGAGGUCUAGGGUCCUGCUTsT 36% 2% ND-10738 1195 UUCGAGUUCUUCUGCAACATsT 1196  UGUUGCAGAAGAACUCGAATsT 13% 1% ND-107391197  CACCAUCCACGGCGCCAUCTsT 1198  GAUGGCGCCGUGGAUGGUGTsT 13% 2%ND-10740 1199  CCACGGCGCCAUCCGCCUGTsT 1200  CAGGCGGAUGGCGCCGUGGTsT 44%4% ND-10741 1201  CAGCACAACCGCAUGAAGATsT 1202  UCUUCAUGCGGUUGUGCUGTsT23% 3% ND-10742 1203  CCUUUGGCAUGAUGUACUGTsT 1204 CAGUACAUCAUGCCAAAGGTsT 12% 1% ND-10743 1205  AUCCUGCUGAGGCUGCCAGTsT1206  CUGGCAGCCUCGACAGGAUTsT 14% 3% ND-10744 1207 UCUCCUGCAACCAGGCGAATsT 1208  UUCGCCUGGUUGCAGGAGATsT 12% 1% ND-107451209  UGCAACCAGGCGAAUUACUTsT 1210  AGUAAUUCGCCUGGUUGCATsT 45% 5%ND-10746 1211  ACCUCCAUCAGCAUGAGGATsT 1212  UCCUCAUGCUGAUGGAGGUTsT 82%7% ND-10747 1213  GCGACUGCACCAAGAAUGGTsT 1214  CCAUUCUUGGUGCAGUCGCTsT82% 19%  ND-10748 1215  ACCAAGAAUGGCAGUGAUGTsT 1216 CAUCACUGCCAUUCUUGGUTsT 54% 18%  ND-10749 1217  UGGUUACUCACGAUGGCCCTsT1218  GGGCCAUCGUGAGUAACCATsT 45% 7% ND-10750 1219 AGAAAUGGAGUGGCCAAAGTsT 1220  CUUUGGCCACUCCAUUUCUTsT 11% 3% ND-107511221  GGAGCUGAACUACAAAACCTsT 1222  GGUUUUGUAGUUCAGCUCCTsT 15% 3%ND-10752 1223  CCUCUGUCACGAUGGUCACTsT 1224  GUGACCAUCGUGACAGAGGTsT 18%5% ND-10753 1225  AGAUUGAAGGAUGUGCAGGTsT 1226  CCUGCACAUCCUUCAAUCUTsT26% 3% ND-10754 1227  GAGCUUUGACAAGGAACUUTsT 1228 AAGUUCCUUGUCAAAGCUCTsT 14% 2% ND-10755 1229  CUUUGACAAGGAACUUUCCTsT1230  GGAAAGUUCCUUGUCAAAGTsT 50% 8% ND-10756 1231 UCAGACACCAUUACUUUUGTsT 1232  CAAAAGUAAUGGUGUCUGATsT 32% 4% ND-107571233  AGCACACUAUAACAUCUGCTsT 1234  GCAGAUGUUAUAGUGUGCUTsT 11% 2%ND-10758 1235  GCACAACCGCAUGAAGACGTsT 1236  CGUCUUCAUGCGGUUGUGCTsT 34%3% ND-10759 1237  ACUGCUUCUACCAGACAUATsT 1238  UAUGUCUGGUAGAAGCAGUTsT11% 1% ND-10760 1239  GAAGACGGCCUUCUGGGCATsT 1240 UGCCCAGAAGGCCGUCUUCTsT 16% 2% ND-10761 1241  AAGACGGCCUUCUGGGCAGTsT1242  CUGCCCAGAAGGCCGUCUUTsT 58% 21%  ND-10762 1243 ACAUCAACCUCAACUCGGATsT 1244  UCCGAGUUGAGGUUGAUGUTsT 14% 3% ND-107631245  UGGAAGGACUGGAAGAUCGTsT 1246  CGAUCUUCCAGUCCUUCCATsT 109%  29% ND-10764 1247  ACAUCCUGUCGAGGCUGCCTsT 1248  GGCAGCCUCGACAGGAUGUTsT 101% 13%  ND-10765 1249  CAACCAGGCGAAUUACUCUTsT 1250  AGAGUAAUUCGCCUGGUUGTsT19% 5% ND-10766 1251  CAGGCGAAUUACUCUCACUTsT 1252 AGUGAGAGUAAUUCGCCUGTsT 24% 4% ND-10767 1253  AGCAGAAUGACUUCAUUCCTsT1254  GGAAUGAAGUCAUUCUGCUTsT 40% 8% ND-10768 1255 AUGAUGGUGGCUUUAACUUTsT 1256  AAGUUAAAGCCACCAUCAUTsT 85% 8% ND-107691257  AGAACCUUUACCCUUCAAATsT 1258  UUUGAAGGGUAAAGGUUCUTsT 22% 4%ND-10770 1259  CCUUUACCCUUCAAAGUACTsT 1260  GUACUUUGAAGGGUAAAGGTsT 21%4% ND-10771 1261  GAGCCUGUGGUUCGGCUCCTsT 1262  GGAGCCGAACCACAGGCUCTsT28% 1% ND-10772 1263  UGGUACUGCCUCUGAACACTsT 1264 GUGUUCAGAGGCAGUACCATsT 58% 4% ND-10773 1265  CUCAUACCCGUGCCCUCACTsT1266  GUGAGGGCACGGGUAUGAGTsT 15% 2% ND-10774 1267 CCGUAGCACACUAUAACAUTsT 1268  AUGUUAUAGUGUGCUACGGTsT 24% 6% ND-107751269  CGUAGCACACUAUAACAUCTsT 1270  GAUGUUAUAGUGUGCUACGTsT 21% 4%ND-10776 1271  GCAGGACCCUAGACCUCUGTsT 1272  CAGAGGUCUAGGGUCCUGCTsT 25%4% ND-10777 1273  GCCUGCUUUUCGGAGAGUATsT 1274  UACUCUCCGAAAAGCAGGCTsT18% 4% ND-10778 1275  GGGCCCGGGUAAUGGUGCATsT 1276 UGCACCAUUACCCGGGCCCTsT 16% 2% ND-10779 1277  CAACAACAAGAGAAAUGGATsT1278  UCCAUUUCUCUUGUUGUUGTsT 17% 0% ND-10780 1279 GCUGUUGCACCAUACUUUCTsT 1280  GAAAGUAUGGUGCAACAGCTsT 14% 1% ND-107811281  CUACCGAGAGCUCUUCGAGTsT 1282  CUCGAAGAGCUCUCGGUAGTsT 24% 3%ND-10782 1283  ACCUGCCUUUAUGGAUGAUTsT 1284  AUCAUCCAUAAAGGCAGGUTsT 115% 10%  ND-10783 1285  UUGACAAGGAACUUUCCUATsT 1286  UAGGAAAGUUCCUUGUCAATsT16% 1% ND-10784 1287  GCUGGAGUGUUGCUGUUGCTsT 1288 GCAACAGCAACACUCCAGCTsT 12% 1% ND-10785 1289  UCGGUGACAUCCCAGGAAUTsT1290  AUUCCUGGGAUGUCACCGATsT 28% 1% ND-10786 1291 GCUGCCCAGAAGUGCCUUGTsT 1292  CAAGGCACUUCUGGGCAGCTsT 15% 2% ND-107871293  AGUACACACAGCAGGUGUGTsT 1294  CACACCUGCUGUGUGUACUTsT 12% 1%ND-10788 1295  CAAGUGCCGGAAGCCAUGCTsT 1296  GCAUGGCUUCCGGCACUUGTsT 94%2%

Table 1C: Selected siRNAs in in vivo rat surrogate set (human-ratcross-reactive siRNAs with highest specificity in rat). A screening setof 48 human and rat cross-reactive alpha-ENaC iRNA sequences wereidentified. The percentage residual expression of alpha-ENaC in twoindependent single-dose transfection experiments is shown (refer toexamples section for methods used).

TABLE 1C 1st screen single dose 2nd screen @ 50 nM in @ 50 nM Duplex IDSeq ID Sense Seq ID Antisense H441; MV SD in H441 SD ND-9201 1297uGuGcAAccAGAAcAAAucTsT 1298 GAUUUGUUCUGGUUGcAcATsT 80% 1%  8% 1% ND-92021299 uuuAuGGAuGAuGGuGGcuTsT 1300 AGCcACcAUcAUCcAuAAATsT 80% 9% 82% 6%ND-9203 1301 GccuuuAuGGAuGAuGGuGTsT 1302 cACcAUcAUCcAuAAAGGCTsT 76% 8%76% 2% ND-9204 1303 cAcAAccGcAuGAAGAcGGTsT 1304 CCGUCUUcAUGCGGUUGUGTsT73% 18%  57% 3% ND-9205 1305 AccGcAuGAAGAcGGccuuTsT 1306AAGGCCGUCUUcAUGCGGUTsT 35% 3% 37% 2% ND-9206 1307 AGGAcuGGAAGAucGGcuuTsT1308 AAGCCGAUCUUCcAGUCCUTsT 17% 3% 16% 3% ND-9207 1309GAAGGAcuGGAAGAucGGcTsT 1310 GCCGAUCUUCcAGUCCUUCTsT 96% 18%  81% 5%ND-9208 1311 GGAcuGGAAGAucGGcuucTsT 1312 GAAGCCGAUCUUCcAGUCCTsT 58% 6%57% 3% ND-9209 1313 AGuuccAccGcuccuAccGTsT 1314 CGGuAGGAGCGGUGGAACUTsT85% 8% 94% 4% ND-9210 1315 GAcuGGAAGAucGGcuuccTsT 1316GGAAGCCGAUCUUCcAGUCTsT 79% 5% 82% 2% ND-9211 1317 cGcAuGAAGAcGGccuucuTsT1318 AGAAGGCCGUCUUcAUGCGTsT 50% 1% 51% 1% ND-9212 1319GccAGuGGAGccuGuGGuuTsT 1320 AACcAcAGGCUCcACUGGCTsT 26% 3% 23% 2% ND-92131321 uGccuuuAuGGAuGAuGGuTsT 1322 ACcAUcAUCcAuAAAGGcATsT 77% 5% 76% 4%ND-9214 1323 uccuGuccAAccuGGGcAGTsT 1324 CUGCCcAGGUUGGAcAGGATsT 74% 9%83% 6% ND-9215 1325 AGGGAGuGGuAccGcuuccTsT 1326 GGAAGCGGuACcACUCCCUTsT79% 6% 89% 4% ND-9216 1327 GGcuGuGccuAcAucuucuTsT 1328AGAAGAUGuAGGcAcAGCCTsT 11% 1% 13% 1% ND-9217 1329 GAAAuuAAAGAGGAGcuGGTsT1330 CcAGCUCCUCUUuAAUUUCTsT 84% 14%  78% 5% ND-9218 1331AcuGGAAGAucGGcuuccATsT 1332 UGGAAGCCGAUCUUCcAGUTsT 50% 4% 55% 3% ND-92191333 ccuGuccAAccuGGGcAGcTsT 1334 GCUGCCcAGGUUGGAcAGGTsT 78% 6% 85% 5%ND-9220 1335 ccuGccuuuAuGGAuGAuGTsT 1336 cAUcAUCcAuAAAGGcAGGTsT 76% 5%77% 9% ND-9221 1337 AAccGcAuGAAGAcGGccuTsT 1338 AGGCCGUCUUcAUGCGGUUTsT79% 8% 66% 3% ND-9222 1339 uGuccAAccuGGGcAGccATsT 1340UGGCUGCCcAGGUUGGAcATsT 70% 4% 57% 4% ND-9223 1341 GuccAAccuGGGcAGccAGTsT1342 CUGGCUGUUcAGGUUGGACTsT 95% 10%  76% 4% ND-9224 1343AAAuuAAAGAGGAGcuGGATsT 1344 UCcAGCUCCUCUUuAAUUUTsT 83% 6% 69% 2% ND-92251345 GGAAGGAcuGGAAGAucGGTsT 1346 CCGAUCUUCcAGUCCUUCCTsT 41% 2% 30% 2%ND-9226 1347 GuGAGGGAGuGGuAccGcuTsT 1348 AGCGGuACcACUCCCUcACTsT 21% 1%17% 0% ND-9227 1349 AcuuucAAuGAcAAGAAcATsT 1350 UGUUCUUGUcAUUGAAAGUTsT13% 1% 10% 0% ND-9228 1351 ucAAuGAcAAGAAcAAcucTsT 1352GAGUUGUUCUUGUcAUUGATsT 36% 2% 28% 0% ND-9229 1353 cuuuAuGGAuGAuGGuGGcTsT1354 GCcACcAUcAUCcAuAAAGTsT 24% 1% 20% 1% ND-9230 1355GccuGGcGuGGAGAccuccTsT 1356 GGAGGUCUCcACGCcAGGCTsT ND-9231 1357uGGcGuGGAGAccuccAucTsT 1358 GAUGGAGGUCUCcACGCcATsT 45% 4% 35% 3% ND-92321359 GAGuuccAccGcuccuAccTsT 1360 GGuAGGAGCGGUGGAACUCTsT 89% 4% 86% 8%ND-9233 1361 cAGAGcAGAAuGAcuucAuTsT 1362 AUGAAGUcAUUCUGCUCUGTsT 21% 1%17% 0% ND-9234 1363 uucAcuccuGcuuccAGGATsT 1364 UCCUGGAAGcAGGAGUGAATsT85% 4% 74% 6% ND-9235 1365 ucAcuccuGcuuccAGGAGTsT 1366CUCCUGGAAGcAGGAGUGATsT ND-9236 1367 cuGuGcAAccAGAAcAAAuTsT 1368AUUUGUUCUGGUUGcAcAGTsT 23% 1% 17% 2% ND-9237 1369 cuGcAAcAAcAccAccAucTsT1370 GAUGGUGGUGUUGUUGcAGTsT 34% 2% 27% 2% ND-9238 1371uGuGGcuGuGccuAcAucuTsT 1372 AGAUGuAGGcAcAGCcAcATsT 86% 4% 73% 10% ND-9239 1373 uGGcuGuGccuAcAucuucTsT 1374 GAAGAUGuAGGcAcAGCcATsT 68% 6%53% 4% ND-9240 1375 cuGuccAAccuGGGcAGccTsT 1376 GGCUGCCcAGGUUGGAcAGTsT80% 5% 73% 9% ND-9241 1377 cccuGcuGuccAcAGuGAcTsT 1378GUcACUGUGGAcAGcAGGGTsT 83% 5% 71% 5% ND-9242 1379 GcAGccAGuGGAGccuGuGTsT1380 cAcAGGCUCcACUGGCUGCTsT 105%  9% 90% 5% ND-9243 1381uucAAuGAcAAGAAcAAcuTsT 1382 AGUUGUUCUUGUcAUUGAATsT 23% 3% 21% 1% ND-92441383 cuGccuuuAuGGAuGAuGGTsT 1384 CcAUcAUCcAuAAAGGcAGTsT 74% 6% 64% 7%ND-9245 1385 AAuGAcAAGAAcAAcuccATsT 1386 UGGAGUUGUUCUUGUcAUUTsT 21% 1%21% 1% ND-9246 1387 uGGGcAGccAGuGGAGccuTsT 1388 AGGCUCcACUGGCUGCCcATsT83% 3% 73% 2% ND-9247 1389 cuccuGuccAAccuGGGcATsT 1390UGCCcAGGUUGGAcAGGAGTsT 86% 3% 84% 1% ND-9248 1391 GGcGuGGAGAccuccAucATsT1392 UGAUGGAGGUCUCcACGCCTsT 92% 4% 88% 3%

Table 1D: Selected siRNAs in in vivo guinea pig surrogate set(human-guinea pig cross-reactive siRNAs). A screening set of 63 humanand guinea-pig cross-reactive alpha-ENaC iRNA sequences were identifiedand synthesised, both with (sequence strands 1393-1518) and without(sequence strands 1519-16) backbone modification. The percentageresidual expression of alpha-ENaC in two independent single-dosetransfection experiments is shown (refer to examples section for methodsused).

TABLE 1D 1st screen single dose 2nd screen @ 50 nM in @ 50 nM Duplex IDSeq ID Sense Seq ID Antisense H441; MV SD in H441 SD ND8437 1393AAucGGAcuGcuucuAccATsT 1394 UGGuAGAAGcAGUCCGAUUTsT 48% 7% 46% 5% ND84381395 AucGGAcuGcuucuAccAGTsT 1396 CUGGuAGAAGcAGUCCGAUTsT 85% 5% 93% 13% ND8439 1397 AAAucGGAcuGcuucuAccTsT 1398 GGuAGAAGcAGUCCGAUUUTsT 36% 3%42% 6% ND8440 1399 ucGGAcuGcuucuAccAGATsT 1400 UCUGGuAGAAGcAGUCCGATsT45% 3% 50% 4% ND8441 1401 AccAGAAcAAAucGGAcuGTsT 1402cAGUCCGAUUUGUUCUGGUTsT 23% 3% 24% 6% ND8442 1403 ccAGAAcAAAucGGAcuGcTsT1404 GcAGUCCGAUUUGUUCUGGTsT 50% 6% 39% 9% ND8443 1405cAGAAcAAAucGGAcuGcuTsT 1406 AGcAGUCCGAUUUGUUCUGTsT 22% 2% 24% 1% ND84441407 cuucGccuGccGcuucAAcTsT 1408 GUUGAAGCGGcAGGCGAAGTsT 111%  8% 109% 4% ND8445 1409 uGGuAccGcuuccAcuAcATsT 1410 UGuAGUGGAAGCGGuACcATsT 84% 7%97% 13%  ND8446 1411 AucuucGccuGccGccucATsT 1412 UGAAGCGGcAGGCGAAGAUTsT90% 3% 121%  13%  ND8447 1413 uucGccuGccGcuucAAccTsT 1414GGUUGAAGCGGcAGGCGAATsT 92% 2% 105%  17%  ND8448 1415cAcccucAAucccuAcAGGTsT 1416 CCUGuAGGGAUUGAGGGUGTsT 79% 3% 90% 13% ND8449 1417 AGAAcAAAucGGAcuGcuuTsT 1418 AAGcAGUCCGAUUUGUUCUTsT 11% 0%17% 3% ND8450 1419 GAAcAAAucGGAcuGcuucTsT 1420 GAAGcAGUCCGAUUUGUUCTsT21% 1% 30% 5% ND8451 1421 cGGAcuGcuucuAccAGAcTsT 1422GUCUGGuAGAAGcAGUCCGTsT 24% 2% 32% 5% ND8452 1423 AGccucAAcAucAAccucATsT1424 UGAGGUUGAUGUUGAGGCUTsT 51% 3% 57% 4% ND8453 1425GccucAAcAucAAccucAATsT 1426 UUGAGGUUGAUGUUGAGGCTsT 16% 1% 26% 3% ND84541427 GucAGccucAAcAucAAccTsT 1428 GGUUGAUGUUGAGGCUGACTsT 62% 5% 68% 6%ND8455 1429 ucAGccucAAcAucAAccuTsT 1430 AGGUUGAUGUUGAGGCUGATsT 77% 4%87% 6% ND8456 1431 cAGccucAAcAucAAccucTsT 1432 GAGGUUGAUGUUGAGGCUGTsT34% 2% 51% 8% ND8457 1433 GGAGcuGGAccGcAucAcATsT 1434UGUGAUGCGGUCcAGCUCCTsT 26% 2% 17% 1% ND8458 1435 GuAccGcuuccAcuAcAucTsT1436 GAUGuAGUGGAAGCGGuACTsT 101%  9% 99% 11%  ND8459 1437ccGcuuccAcuAcAucAAcTsT 1438 GUUGAUGuAGUGGAAGCGGTsT 85% 8% 80% 6% ND84601439 cGcuuccAcuAcAucAAcATsT 1440 UGUUGAUGuAGUGGAAGCGTsT 56% 6% 48% 3%ND8461 1441 uuccAcuAcAucAAcAuccTsT 1442 GGAUGUUGAUGuAGUGGAATsT 77% 5%82% 7% ND8462 1443 uGGGcAAcuucAucuucGcTsT 1444 GCGAAGAUGAAGUUGCCcATsT21% 0% 36% 6% ND8463 1445 GcAAcuucAucuucGccuGTsT 1446cAGGCGAAGAUGAAGUUGCTsT 80% 4% 84% 13%  ND8464 1447cAAcuucAucuucGccuGcTsT 1448 GcAGGCGAAGAUGAAGUUGTsT 101%  1% 102%  14% ND8465 1449 AAcuucAucuucGccuGccTsT 1450 GGcAGGCGAAGAUGAAGUUTsT 100%  4%95% 12%  ND8466 1451 AcuucAucuucGccuGccGTsT 1452 CGGcAGGCGAAGAUGAAGUTsT51% 4% 49% 5% ND8467 1453 cuucAucuucGccuGccGcTsT 1454GCGGcAGGCGAAGAUGAAGTsT 95% 5% 89% 4% ND8468 1455 ucAucuucGccuGccGcuuTsT1456 AAGCGGcAGGCGAAGAUGATsT 91% 4% 85% 6% ND8469 1457cAucuucGccuGccGcuucTsT 1458 GAAGCGGcAGGCGAAGAUGTsT 66% 4% 55% 4% ND84701459 ucuucGccuGccGcuucAATsT 1460 UUGAAGCGGcAGGCGAAGATsT 97% 2% 99% 11% ND8471 1461 cGccuGccGcuucAAccAGTsT 1462 CUGGUUGAAGCGGcAGGCGTsT 96% 4%100%  7% ND8472 1463 GccuGccGcuucAAccAGGTsT 1464 CCUGGUUGAAGCGGcAGGCTsT90% 4% 82% 5% ND8473 1465 AuuAcucucAcuuccAccATsT 1466UGGUGGAAGUGAGAGuAAUTsT 81% 3% 72% 4% ND8474 1467 uuAcucucAcuuccAccAcTsT1468 GUGGUGGAAGUGAGAGuAATsT 72% 2% 76% 9% ND8475 1469AcucucAcuuccAccAcccTsT 1470 GGGUGGUGGAAGUGAGAGUTsT 90% 3% 97% 4% ND84761471 ucuGcAcccucAAucccuATsT 1472 uAGGGAUUGAGGGUGcAGATsT 61% 1% 63% 3%ND8477 1473 cuGcAcccucAAucccuAcTsT 1474 GuAGGGAUUGAGGGUGcAGTsT 74% 3%73% 1% ND8478 1475 uGcAcccucAAucccuAcATsT 1476 UGuAGGGAUUGAGGGUGcATsT98% 4% 85% 1% ND8479 1477 AcccucAAucccuAcAGGuTsT 1478ACCUGuAGGGAUUGAGGGUTsT 55% 5% 48% 3% ND8480 1479 cccucAAucccuAcAGGuATsT1480 uACCUGuAGGGAUUGAGGGTsT 20% 1% 14% 1% ND8481 1481ccucAAucccuAcAGGuAcTsT 1482 GuACCUGuAGGGAUUGAGGTsT 40% 2% 31% 3% ND84821483 AAccAGAAcAAAucGGAcuTsT 1484 AGUCCGAUUUGUUCUGGUUTsT 57% 2% 52% 0%ND8483 1485 AAcAAAucGGAcuGcuucuTsT 1486 AGAAGcAGUCCGAUUUGUUTsT 102%  5%86% 12%  ND8484 1487 AcAAAucGGAcuGcuucuATsT 1488 uAGAAGcAGUCCGAUUUGUTsT40% 2% 28% 3% ND8485 1489 cAAAucGGAcuGcuucuAcTsT 1490GuAGAAGcAGUCCGAUUUGTsT 41% 4% 38% 2% ND8486 1491 GcAcccucAAucccuAcAGTsT1492 CUGuAGGGAUUGAGGGUGCTsT 91% 7% 94% 4% ND8487 1493ccucAAcAucAAccucAAcTsT 1494 GUUGAGGUUGAUGUUGAGGTsT 46% 2% 37% 3% ND84881495 cucAAcAucAAccucAAcuTsT 1496 AGUUGAGGUUGAUGUUGAGTsT 48% 2% 39% 3%ND8489 1497 ucAAcAucAAccucAAcucTsT 1498 GAGUUGAGGUUGAUGUUGATsT 17% 1%17% 1% ND8490 1499 uAccGcuuccAcuAcAucATsT 1500 UGAUGuAGUGGAAGCGGuATsT90% 5% 74% 8% ND8491 1501 AccGcuuccAcuAcAucAATsT 1502UUGAUGuAGUGGAAGCGGUTsT 103%  4% 91% 15%  ND8492 1503GcuuccAcuAcAucAAcAuTsT 1504 AUGUUGAUGuAGUGGAAGCTsT 85% 3% 71% 10% ND8493 1505 cuuccAcuAcAucAAcAucTsT 1506 GAUGUUGAUGuAGUGGAAGTsT 60% 5%45% 3% ND8494 1507 uccAcuAcAucAAcAuccuTsT 1508 AGGAUGUUGAUGuAGUGGATsT33% 3% 41% 3% ND8495 1509 ccAcuAcAucAAcAuccuGTsT 1510cAGGAUGUUGAUGuAGUGGTsT 60% 5% 55% 2% ND8496 1511 cuGGGcAAcuucAucuucGTsT1512 CGAAGAUGAAGUUGCCcAGTsT 18% 0% 20% 0% ND8497 1513GGcAAcuucAucuucGccuTsT 1514 AGGCGAAGAUGAAGUUGCCTsT 76% 1% 77% 2% ND84981515 uucAucuucGccuGccGcuTsT 1516 AGCGGcAGGCGAAGAUGAATsT 65% 4% 74% 12% ND8499 1517 ucGccuGccGcuucAAccATsT 1518 UGGUUGAAGCGGcAGGCGATsT 86% 5%77% 3% ND-8653 1519 AAUCGGACUGCUUCUACCATsT 1520 UGGUAGAAGCAGUCCGAUUTsT16% 2% 20% 3% ND-8654 1521 AUCGGACUGCUUCUACCAGTsT 1522CUGGUAGAAGCAGUCCGAUTsT 54% 8% 67% 11%  ND-8655 1523AAAUCGGACUGCUUCUACCTsT 1524 GGUAGAAGCAGUCCGAUUUTsT 25% 4% 28% 2% ND-86561525 UCGGACUGCUUCUACCAGATsT 1526 UCUGGUAGAAGCAGUCCGATsT 12% 2% 17% 1%ND-8657 1527 ACCAGAACAAAUCGGACUGTsT 1528 CAGUCCGAUUUGUUCUGGUTsT 33% 3%35% 1% ND-8658 1529 CCAGAACAAAUCGGACUGCTsT 1530 GCAGUCCGAUUUGUUCUGGTsT27% 3% 30% 2% ND-8659 1531 CAGAACAAAUCGGACUGCUTsT 1532AGCAGUCCGAUUUGUUCUGTsT 15% 1% 22% 3% ND-8660 1533 CUUCGCCUGCCGCUUCAACTsT1534 GUUGAAGCGGCAGGCGAAGTsT 69% 17%  75% 10%  ND-8661 1535UGGUACCGCUUCCACUACATsT 1536 UGUAGUGGAAGCGGUACCATsT 16% 2% 20% 3% ND-86621537 AUCUUCGCCUGCCGCUUCATsT 1538 UGAAGCGGCAGGCGAAGAUTsT 19% 2% 25% 4%ND-8663 1539 UUCGCCUGCCGCUUCAACCTsT 1540 GGUUGAAGCGGCAGGCGAATsT 90% 4%97% 10%  ND-8664 1541 CACCCUCAAUCCCUACAGGTsT 1542 CCUGUAGGGAUUGAGGGUGTsT19% 2% 25% 3% ND-8665 1543 AGAACAAAUCGGACUGCUUTsT 1544AAGCAGUCCGAUUUGUUCUTsT 13% 1% 22% 2% ND-8666 1545 GAACAAAUCGGACUGCUUCTsT1546 GAAGCAGUCCGAUUUGUUCTsT 11% 2% 18% 2% ND-8667 1547CGGACUGCUUCUACCAGACTsT 1548 GUCUGGUAGAAGCAGUCCGTsT 13% 1% 16% 2% ND-86681549 AGCCUCAACAUCAACCUCATsT 1550 UGAGGUUGAUGUUGAGGCUTsT 17% 4% 21% 3%ND-8669 1551 GCCUCAACAUCAACCUCAATsT 1552 UUGAGGUUGAUGUUGAGGCTsT 13% 1%21% 3% ND-8670 1553 GUCAGCCUCAACAUCAACCTsT 1554 GGUUGAUGUUGAGGCUGACTsT43% 11%  27% 3% ND-8671 1555 UCAGCCUCAACAUCAACCUTsT 1556AGGUUGAUGUUGAGGCUGATsT 90% 17%  53% 13%  ND-8672 1557CAGCCUCAACAUCAACCUCTsT 1558 GAGGUUGAUGUUGAGGCUGTsT 17% 3% 11% 3% ND-86731559 GGAGCUGGACCGCAUCACATsT 1560 UGUGAUGCGGUCCAGCUCCTsT 25% 3% 18% 3%ND-8674 1561 GUACCGCUUCCACUACAUCTsT 1562 GAUGUAGUGGAAGCGGUACTsT 21% 4%16% 4% ND-8675 1563 CCGCUUCCACUACAUCAACTsT 1564 GUUGAUGUAGUGGAAGCGGTsT25% 4% 19% 3% ND-8676 1565 CGCUUCCACUACAUCAACATsT 1566UGUUGAUGUAGUGGAAGCGTsT 16% 3% 14% 1% ND-8677 1567 UUCCACUACAUCAACAUCCTsT1568 GGAUGUUGAUGUAGUGGAATsT 110%  19%  97% 9% ND-8678 1569UGGGCAACUUCAUCUUCGCTsT 1570 GCGAAGAUGAAGUUGCCCATsT 50% 8% 40% 5% ND-86791571 GCAACUUCAUCUUCGCCUGTsT 1572 CAGGCGAAGAUGAAGUUGCTsT 19% 3% 17% 2%ND-8680 1573 CAACUUCAUCUUCGCCUGCTsT 1574 GCAGGCGAAGAUGAAGUUGTsT 25% 2%23% 2% ND-8681 1575 AACUUCAUCUUCGCCUGCCTsT 1576 GGCAGGCGAAGAUGAAGUUTsT104%  7% 85% 10%  ND-8682 1577 ACUUCAUCUUCGCCUGCCGTsT 1578CGGCAGGCGAAGAUGAAGUTsT 91% 8% 63% 9% ND-8683 1579 CUUCAUCUUCGCCUGCCGCTsT1580 GCGGCAGGCGAAGAUGAAGTsT 88% 6% 58% 6% ND-8684 1581UCAUCUUCGCCUGCCGCUUTsT 1582 AAGCGGCAGGCGAAGAUGATsT 76% 3% 64% 4% ND-86851583 CAUCUUCGCCUGCCGCUUCTsT 1584 GAAGCGGCAGGCGAAGAUGTsT 15% 1% 18% 3%ND-8686 1585 UCUUCGCCUGCCGCUUCAATsT 1586 UUGAAGCGGCAGGCGAAGATsT 109% 22%  31% 3% ND-8687 1587 CGCCUGCCGCUUCAACCAGTsT 1588CUGGUUGAAGCGGCAGGCGTsT 90% 21%  49% 2% ND-8688 1589GCCUGCCGCUUCAACCAGGTsT 1590 CCUGGUUGAAGCGGCAGGCTsT 43% 9% 24% 7% ND-86891591 AUUACUCUCACUUCCACCATsT 1592 UGGUGGAAGUGAGAGUAAUTsT 27% 4% 19% 2%ND-8690 1593 UUACUCUCACUUCCACCACTsT 1594 GUGGUGGAAGUGAGAGUAATsT 109%  7%85% 8% ND-8691 1595 ACUCUCACUUCCACCACCCTsT 1596 GGGUGGUGGAAGUGAGAGUTsT93% 11%  87% 12%  ND-8692 1597 UCUGCACCCUCAAUCCCUATsT 1598UAGGGAUUGAGGGUGCAGATsT 31% 12%  17% 2% ND-8693 1599CUGCACCCUCAAUCCCUACTsT 1600 GUAGGGAUUGAGGGUGCAGTsT 41% 25%  31% 4%ND-8694 1601 UGCACCCUCAAUCCCUACATsT 1602 UGUAGGGAUUGAGGGUGCATsT 75% 25% 43% 3% ND-8695 1603 ACCCUCAAUCCCUACAGGUTsT 1604 ACCUGUAGGGAUUGAGGGUTsT65% 26%  25% 5% ND-8696 1605 CCCUCAAUCCCUACAGGUATsT 1606UACCUGUAGGGAUUGAGGGTsT 18% 2% 13% 1% ND-8697 1607 CCUCAAUCCCUACAGGUACTsT1608 GUACCUGUAGGGAUUGAGGTsT 16% 4% 13% 2% ND-8698 1609AACCAGAACAAAUCGGACUTsT 1610 AGUCCGAUUUGUUCUGGUUTsT 40% 2% 30% 2% ND-86991611 AACAAAUCGGACUGCUUCUTsT 1612 AGAAGCAGUCCGAUUUGUUTsT 56% 4% 45% 3%ND-8700 1613 ACAAAUCGGACUGCUUCUATsT 1614 UAGAAGCAGUCCGAUUUGUTsT 18% 3%12% 1% ND-8701 1615 CAAAUCGGACUGCUUCUACTsT 1616 GUAGAAGCAGUCCGAUUUGTsT15% 2% 15% 4% ND-8702 1617 GCACCCUCAAUCCCUACAGTsT 1618CUGUAGGGAUUGAGGGUGCTsT 53% 4% 46% 20%  ND-8703 1619CCUCAACAUCAACCUCAACTsT 1620 GUUGAGGUUGAUGUUGAGGTsT 25% 6% 26% 9% ND-87041621 CUCAACAUCAACCUCAACUTsT 1622 AGUUGAGGUUGAUGUUGAGTsT 30% 8% 37% 26% ND-8705 1623 UCAACAUCAACCUCAACUCTsT 1624 GAGUUGAGGUUGAUGUUGATsT 55% 1%50% 10%  ND-8706 1625 UACCGCUUCCACUACAUCATsT 1626 UGAUGUAGUGGAAGCGGUATsT36% 7% 31% 7% ND-8707 1627 ACCGCUUCCACUACAUCAATsT 1628UUGAUGUAGUGGAAGCGGUTsT 23% 5% 27% 10%  ND-8708 1629GCUUCCACUACAUCAACAUTsT 1630 AUGUUGAUGUAGUGGAAGCTsT 16% 4% 24% 12% ND-8709 1631 CUUCCACUACAUCAACAUCTsT 1632 GAUGUUGAUGUAGUGGAAGTsT 62% 3%74% 27%  ND-8710 1633 UCCACUACAUCAACAUCCUTsT 1634 AGGAUGUUGAUGUAGUGGATsT45% 8% 41% 1% ND-8711 1635 CCACUACAUCAACAUCCUGTsT 1636CAGGAUGUUGAUGUAGUGGTsT 23% 4% 27% 10%  ND-8712 1637CUGGGCAACUUCAUCUUCGTsT 1638 CGAAGAUGAAGUUGCCCAGTsT 34% 4% 26% 5% ND-87131639 GGCAACUUCAUCUUCGCCUTsT 1640 AGGCGAAGAUGAAGUUGCCTsT 30% 3% 23% 2%ND-8714 1641 UUCAUCUUCGCCUGCCGCUTsT 1642 AGCGGCAGGCGAAGAUGAATsT 90% 14% 85% 14%  ND-8715 1643 UCGCCUGCCGCUUCAACCATsT 1644 UGGUUGAAGCGGCAGGCGATsT23% 2% 20% 4

TABLE 2A Concentration at 50% inhibition (IC50) for exemplary iRNAagents of Table 1A IC50 [nM] IC50 [nM] 1st DRC in 2nd DRC in Duplex IDH441 H441 ND8294 0.1949 0.0468 ND8295 0.1011 0.0458 ND8299 0.5986 0.5638ND8302 0.0144 0.0134 ND8313 0.0315 0.0124 ND8320 0.0796 0.0078 ND83310.0213 0.0158 ND8332 0.0205 0.0089 ND8343 0.0523 0.0293 ND8348 0.01560.0182 ND8356 0.0241 0.0099 ND8357 0.0054 0.0032 ND8363 0.1186 0.0337ND8368 0.0487 0.1209 ND8371 0.0811 0.0911 ND8372 0.0584 0.0425 ND83730.0066 0.0165 ND8375 0.1176 0.1187 ND8380 0.6817 0.5747 ND8381 0.00370.0041 ND8383 0.0275 0.1257 ND8384 0.0357 0.0082 ND8391 0.0260 0.0349ND8392 0.3831 0.4775 ND8396 0.0023 0.0052 ND8403 0.0808 0.0759

TABLE 2B Concentration at 50% inhibition (IC50) and for exemplary iRNAagents of Table 1D IC50 [nM] IC50 [nM] 1st DRC in 2nd DRC in Duplex IDH441 H441 ND8441 0.6738 0.8080 ND8443 0.0346 0.0263 ND8449 0.0120 0.0067ND8450 0.0257 0.0106 ND8451 0.1320 0.0931 ND8453 0.0079 0.0033 ND84890.1640 0.1593 ND8496 0.0387 0.0185

TABLE 2C % Activity of the exemplary RNAi towards inhibition ofalpha-ENaC gene expression in the assays described in Example 3 %alpha-ENaC expression in Cynomolgous alpha-ENaC primary HBEC (% ofexpression (% of Duplex identifier control)50 nM siRNA control) 45 nMsiRNA Untransfected 77.2 n/a Non-targetting 100 93.3 Control NegativeControl n/a 100 (Non-cyno alpha- ENaC)ND8449 ND-8302 30.2 57 ND-833224.7 54.3 ND-8348 40.1 56.2 ND-8356 36.6 55.8 ND-8357 29.6 50.4 ND-837330.4 53.8 ND-8381 32.5 40.4 ND-8396 34.1 46.3 ND-8450 45.9 78.9 ND-845330.1 55.3

TABLE 3A DNA sequence of cynomologous mondkey alpha-EnaC (SEQ IDNO:1682) GAATTCGCCCTTGGCCGCTGCACCTGTAGGGGAACAAGCTGGAGGAGCAGGACCCTAGACCTCTGCAGCCCACCGCAGGGCTCATGGAGGGGAACAAGCTGGAGGAGCAGGACGCTAGCCCTCCACAGCCCACCCCAGGGCTCATGAAGGGGGACAAGCGTGAGGAGCAGGGGCTGGGCCCAGAACCTGCGGCACCCCAGCAGCCCACGGCGGAGGAGGAGGCCCTGATCGAGTTCCACCGCTCCTACCGAGAGCTCTTCGAGTTCTTCTGCAACAATACCACCATCCACGGCGCCATCCGCCTGGTGTGCTCCCAGCACAACCGCATGAAGACGGCCTTCTGGGCAGTGCTCTGGCTCTGCACCTTTGGCATGATGTACTGGCAATTCGGCCTGCTTTTCGGAGAGTACTTCAGCTACCCCGTCAGCCTCAACATCAACCTCAACTCGGACAAGCTTGTCTTCCCCGCAGTGACCATCTGCACCCTCAATCCCTACAGGTATCCGGAAATTAAAGAGGAGCTGGAGGAGCTGGACCGCATCACACAGCAGACGCTCTTTGACCTGTACAAATACGACTCCTCCCCCACCCTCGTGGCCGGCTCCCGCGGCCGTCGTGACCTGCGGGGCACTCTGCCGCACCTCTTGCAGCGCCTGAGGGTCCCGTCCCCGCTTCACGGGGCCCGTCAAGCCCGTAGCGTGGCCTCCAGCGTGCGGGACAACAACCCCCAAGTGGACTGGAAGGACTGGAAGATCGGTTTCGAGCTGTGCAACCAGAACAAATCAGACTGCTTCTACCAGACATACTCATCAGGGGTGGATGCAGTGAGGGAGTGGTACCGCTTCCACTACATCAACATCCTGTCGAGGCTGCCAGAGACTCTGCCATCCCTGGAGGAGGACACACTGGGCAACTTCATCTTCGCCTGCCGCTTCAACCAGGTCTCCTGCAACCAGGCGAATTACTCTCACTTCCACCACCCAATGTATGGAAACTGCTATACTTTCAATGACAAGAACAACTCTAACCTCTGGATGTCTTCCATGCCTGGAGTCAACAACGGTCTGTCCCTGATGCTGCGCACAGAGCAGAATGACTTCATTCCCCTGCTGTCCACAGTGACTGGGGCCCGGGTAATGGTGCACGGGCAGGATGAACCTGCCTTTATGGATGATGGTGGCTTTAACTTGCGGCCTGGCGTGGAGACCTCCATCAGCATGAGGAAGGAAGCCCTGGACAGACTTGGGGGCGACTATGGCGACTGCACCAAGAATGGCAGTGATGTCCCTGTCAAGAACCTTTACCCTTCAAAGTACACGCAGCAGGTGTGTATTCACTCCTGCTTCCAGGAGAACATGATCAAGGAGTGTGGCTGTGCCTACATCTTCTATCCGCGGCCGCAGAACATGGAGTACTGTGACTACAGGAAGCACAGTTCCTGGGGCTACTGCTACTATAAGCTCCAGGCTGACTTCTCCTCAGACCACCTGGGCTGTTTCACCAAGTGCCGGAAGCCATGCAGTGTGACCAGCTACCAGCTCTCGGCTGGTTACTCACGATGGCCCTCGGTGACATCCCAGGAATGGGTCTTCGAGATGCTATCGCGACAGAACAACTACACCATCAACAACAAGAGAAATGGAGTGGCCAAAGTCAACATCTTCTTCAAGGAGCTGAACTACAAAACCAATTCTGAGTCTCCCTCTGTCACGATGGTCACCCTCCTGTCCAACCTGGGCAGCCAGTGGAGCCTGTGGTTCGGCTCCTCAGTGCTGTCTGTGGTGGAGATGGCTGAGCTCATCTTTGACCTGCTGGTCATCACATTCCTCCTGCTGCTCCGAAGGTTCCGAAGCCGATACTGGTCTCCAGGCCGAGGGGACAGGGGTGCTCAGGAGGTGGCCTCCACCCAGGCATCCTCCCCGCCTTCCCACTTCTGCCCCCACCCCACATCTCTGTACTTGTCCCAACTAGGCCCTGCTCCCTCCCCAGCCTTGACAGCCCCTCCCCCTGCCTATGCCACCCTGGGCCCCTGCCCATCTCCAGGGGGCTCCGCAGGGGCCAGCTCCACTGCCTATCCTCTGGGGGGGCCCTGAGAGAGGAGAGGTTCCTTGCACCAAGGCAGATGCTCCCCTGGTGGGAGGGTGCTGCCCTTGGCAAGATTGAAGGATGTGCAGGGCTTCCTCTCAGAGCCGCCCAAACTGCCCTTGATGTGTGGAGGGGAAGCGAGATGGGTAAGGGGCTCAGGAAGTTGTTCCAAGAACAGTGGCCAATGAAGCTGCCCAGAAGTGCCTTGGCTCTGGCTCTGTACCCCTTGGTACTGCCTCTGAACACTCTGGTTTCCCCACCCAACTGCAGCTAAGTCTCCTTTTCCCTTGGATCAGCCAAGCCAAACTTGGAGCTTTGACAAGGAACTTTCCTAAGAAATGGCTGATGACCAGGACAAAACACAACCAAGGGTACACACAGGCATGCACGCGTTTCCTGCCTGGCGACAGGTGAAGCCAGCCCCTGACTGACCTGGCCACACTGCTCTCCAGTAACACAGATGTCTGCCCCTCATCTTGAACTTGGGTGGGAAACCCCACCCAAAAGCCCCCTTTATTACTTAGGCAATTCCCCTTCCCTGACTCCCGAGAGCCAGGGCCAGAGCAGACCCGTATAAGTAAAGGCAGCTCCAGGGCTCCTCTAGGCTCATACCCGTGCCCTCACAGAGCCATGCTCCAGCGCTTCTGTCCTGTGTCTTTCGTCCCTCTACATGTCTGCTCAAGACATTTTCTCAGCCTGAAAGCTTCCCCAGCCATCTGCCGGAGAACTCCTATGCATCCCTCAGAACCCTGCTCAGACACCATTACTTTTGTGAAGGCTTCTGCCACATCTTGTCGTCCCAAAAATTGATCACTCCCCTTTCTGGTGGGCTCCCGTAGCACACTATAACATCTGCTGGAGTGTTGCTGTTGCACCATACTTTCTTGTACGTTTGTGTCTGCCTCCCCAACTGGACTGTGAGGGCCTTGTGGCCAGGGACTGAGTCTTGCCCGTTTATGTATGCTCCGTGTCTAGCCCATCATCCTGCTTGAAGCAAGTAGGCAGATGCTCAAAA GGGCGAATTCTGCAGATATC

TABLE 3B Protein sequence of cynomologous mondkey alpha-EnaC (SEQ IDNO:1681) which is a Translation of SEQ ID NO:1682.MEGNKLEEQDASPPQPTPGLMKGDKREEQGLGPEPAAPQQPTAEEEALIEFHRSYRELFEFFCNNTTIHGAIRLVCSQHNRMKTAFWAVLWLCTFGMMYWQFGLLFGEYFSYPVSLNINLNSDKLVFPAVTICTLNPYRYPEIKEELEELDRITQQTLFDLYKYDSSPTLVAGSRGRRDLRGTLPHLLQRLRVPSPLHGARQARSVASSVRDNNPQVDWKDWKIGFELCNQNKSDCFYQTYSSGVDAVREWYRFHYINILSRLPETLPSLEEDTLGNFIFACRFNQVSCNQANYSHFHHPMYGNCYTFNDKNNSNLWMSSMPGVNNGLSLMLRTEQNDFIPLLSTVTGARVMVHGQDEPAFMDDGGFNLRPGVETSISMRKEALDRLGGDYGDCTKNGSDVPVKNLYPSKYTQQVCIHSCFQENMIKECGCAYIFYPRPQNMEYCDYRKHSSWGYCYYKLQADFSSDHLGCFTKCRKPCSVTSYQLSAGYSRWPSVTWQEWVFEMLSRQNNYTINNKRNGVAKVNIFFKELNYKTNSESPSVTMVTLLSNLGSQWSLWFGSSVLSVVEMAELIFDLLVITFLLLLRRFRSRYWSPGRGDRGAQEVASTQASSPPSHFCPHPTSLYLSQLGPAPSPALTAPPPAYATLGPC PSPGGSAGASSTAYPLGGP

It is to be understood that while the invention has been described inconduction with the detailed specification detailed above, the foregoingdescription is intended to illustrate and not limit the scope of theinvention, which is defined by the appended claims. While the inventionhas been described in connection with specific embodiments thereof, itwill be further understood that it is capable of modification. Thisapplication is intended to cover variations, uses or adaptations of theinvention following the general principles of the invention, includingsuch departures from the present disclosure that comes within known orcustomary practice within the art to which the present inventionpertains and that can be applied to the essential features disclosedherein.

1. An iRNA agent comprising a sense strand, wherein the sense strandcomprises at least 15 contiguous nucleotides that differ by no more than1, 2, or 3 nucleotides from the sense strand sequences of any one of theagents provided in Tables 1A-1D, agents numbered ND8285-ND10788, and anantisense strand, wherein the antisense strand comprises at least 15contiguous nucleotides that differ by no more than 1, 2, or 3nucleotides from the antisense sequences of any one of the agentsprovided in Tables 1A-1D, agents numbered ND8285-ND10788.
 2. An iRNAagent including a sense strand, wherein the sense strand comprises atleast 15 contiguous nucleotides that differ by no more than 1, 2, or 3nucleotides from the sense strand sequences of any one of the agentsprovided in Tables 1A-1D, agents numbered ND8285-ND10788, and anantisense strand wherein the antisense strand comprises at least 15contiguous nucleotides of the antisense sequences of any one of theagents provided in Tables 1A-1D, agents numbered ND8285-ND10788, andwherein the iRNA agent reduces the expression of alpha-ENaC by more than20%, 30%, 40%, 50%, 60%, 70%, or 80% compared to cells which have notbeen incubated with the iRNA agent.
 3. An iRNA agent comprising a sensestrand and an antisense strand each comprising a sequence of at least16, 17 or 18 nucleotides which is essentially identical to one of thesequences of any one of the agents provided in Tables 1A-1D, agentsnumbered ND8285-ND10788, except that not more than 1, 2 or 3 nucleotidesper strand, respectively, have been substituted by other nucleotides,while essentially retaining the ability to reduce the amount ofalpha-ENaC expression in cells.
 4. An iRNA agent according to claim 1where the agent is selected from ND-8302, ND-8332, ND-8348, ND-8356,ND-8357, ND-8373, ND-8381, ND-8396, ND-8450 and ND-8453.
 5. An iRNAagent according to claim 1 where the agent is selected from ND-8356,ND-8357 and ND-8396.
 6. The iRNA agent of claim 1, wherein the antisenseRNA strand is 30 or fewer nucleotides in length, and the duplex regionof the iRNA agent is 15-30 nucleotide pairs in length.
 7. The iRNA agentof claim 1, comprising a modification that causes the iRNA agent to haveincreased stability in a biological sample.
 8. The iRNA agent of claim1, comprising a phosphorothioate or a 2′-modified nucleotide.
 9. TheiRNA agent of claim 1, comprising at least one 5′-uridine-adenine-3′(5′-ua-3′) dinucleotide wherein the uridine is a 2′-modified nucleotide;at least one 5′-uridine-guanine-3′ (5′-ug-3′) dinucleotide, wherein the5′-uridine is a 2′-modified nucleotide; at least one5′-cytidine-adenine-3′ (5′-ca-3′) dinucleotide, wherein the 5′-cytidineis a 2′-modified nucleotide; or at least one 5′-uridine-uridine-3′(5′-uu-3′) dinucleotide, wherein the 5′-uridine is a 2′-modifiednucleotide.
 10. The iRNA agent of claim 1, wherein the 2′-modificationis selected from the group consisting of: 2′-deoxy, 2′-deoxy-2′-fluoro,2′-O-methyl, 2′-O-methoxyethyl (2′-O-MOE), 2′-O-aminopropyl (2′-O-AP),2′-O-dimethylaminoethyl (2′-O-DMAOE), 2′-O-dimethylaminopropyl(2′-O-DMAP), 2′-O-dimethylaminoethyloxyethyl (2′-O-DMAEOE), and2′-O—N-methylacetamido (2′-O-NMA).
 11. The iRNA agent of claim 1,comprising a nucleotide overhang having 1 to 4 unpaired nucleotides. 12.The iRNA agent of claim 11, wherein the nucleotide overhang has 2 or 3unpaired nucleotides.
 13. The iRNA agent of claim 11, wherein thenucleotide overhang is at the 3′-end of the antisense strand of the iRNAagent.
 14. The iRNA agent of claim 1, comprising an epithelial receptorligand.
 15. The iRNA agent of claim 1, wherein the iRNA agent istargeted for uptake by cells of the lung.
 16. A method of treating ahuman subject having a pathological process mediated at least in part byalpha-ENaC expression, wherein the iRNA agent comprises a sense strandwherein the sense strand comprises at least 15 contiguous nucleotidesthat differ by no more than 1, 2, or 3 nucleotides from the sense strandsequences any one of the agents provided in claim
 1. 17. The method ofclaim 16, wherein the iRNA agent is administered in an amount sufficientto reduce the level of alpha-ENaC expression in a cell or tissue of thesubject.
 18. A pharmaceutical composition, comprising: a) an iRNA agentof claim 1; and b) a pharmaceutically acceptable carrier.
 19. A methodof treating a human subject afflicted with cystic fibrosis which methodcomprises administering to said subject a therapeutically effectiveamount of a iRNA agent of claim
 1. 20. A method of treating a humansubject afflicted with Liddles syndrome which method comprisesadministering to said patient a therapeutically effective amount of aniRNA agent of claim
 1. 21. A method of treating and or preventinghypertension and or renal insufficiency in a human subject which methodcomprises administering to said patient a therapeutically effectiveamount of an iRNA agent of claim
 1. 22. A method of treating and orpreventing an electrolyte imbalance in a human subject which methodcomprises administering to said patient a therapeutically effectiveamount of an iRNA agent of claim 1.